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16
Perianal Dermatology and Pruritus Ani
Charles O. Finne
Perianal skin is subject to virtually all of the diseases that
affect skin in other areas of the body. The differential diagnosis of perianal skin is presented in Table 16-1. This list
includes a variety of diagnoses, which almost never present as
isolated perianal disease, but there are common diseases such
as psoriasis that may present in isolation without obvious ties
to other areas of the body unless a careful search is made.
Successful treatment of perianal disease requires accurate
diagnosis to eliminate diseases that have specific cause and
treatment (e.g., psoriasis, candida, Bowen’s disease).
Recognition of important treatable causes requires a disciplined, organized approach to diagnosis with frequent use of
biopsy. This chapter’s objective is to lay out a strategy to
facilitate accurate diagnosis and successful treatment of perianal and anal skin conditions. Implicit in this strategy is the
ability to properly examine the anus with appropriate instruments and bright light and to understand diseases peculiar to
the anal area, hence, the importance of the colorectal surgeon
who has the skills to accomplish this task. The importance of
complete, accurate evaluation is emphasized by a St. Louis
University series in which a study of 209 patients with the
presenting symptom of pruritus over a 2-year period revealed
that 75% of patients had coexisting anal or colorectal pathology. The diagnoses included 11% with rectal cancer, 6% with
anal canal cancer, and 2% with colon cancer, although the
majority of patients had hemorrhoids or fissure.
1
Definitions
Pruritus ani is a term of Latin derivation, which means itchy
anus. Not only is it a symptom, but the term is a Medline
MeSH searchable diagnosis and is also used to designate a
specific condition of disputed etiology recognized since
antiquity.
no distinction between it and itch, an unpleasant sensation
that provokes the desire to scratch.
chapter, the syndrome will always be referred to as pruritus
ani. Pruritus ani has been classified into primary and second-
2,3
Pruritus used alone simply means itchy: there is
4
To avoid confusion in this
ary. The primary form is the classic syndrome of idiopathic
pruritus ani, whereas the secondary form implies an identifiable cause or a specific diagnosis.
Accurate description of the morphology of skin lesions can
aid in the diagnosis and follow-up of patients with pruritic
complaints. Macules are flat spots. Papules are elevated
circumscribed solid lesions, raised spots. Vesicles are separations of the epidermis and dermis filled with serum. Bulla are
larger vesicles or blisters. Pustules contain pus. Ulcers are
surface lesions with loss of continuity of the skin and may
result from rupture of vesicular lesions, infection, or trauma.
Intertrigo is inflammation seen between two opposing skin
surfaces, often the result of mixed bacterial, fungal infection
associated with moisture, obesity, and poor hygiene.
Physiologic Considerations
Itch is a surface phenomenon mediated by pain fibers in the
epidermis that may have a lower threshold for stimulation
than pain. Itch receptors may be located more superficially
than those dedicated to pain. Because receptors are superficial, innocuous, nondamaging stimuli such as wearing wool,
or other minor mechanical stimuli may induce itching. In
addition to histamine, kallikrein, bradykinin, papain, and
trypsin experimentally produce itching, but these substances
do not respond to blockade with histamine antagonists such as
diphenhydramine, hence topical antihistamines are not
always effective against itching.
esthesia with chronic pain may have a parallel with itching,
whereas minimal stimulation of the skin may induce itching;
scratching with subsequent injury may produce an enlarging
patch of itchy skin. Scratching produces inadequate feedback
to inhibit itching; more scratching occurs with cutaneous
injury, which provides an additional stimulus to scratch in a
self-defeating loop. Substituting heat, cold, painful or stinging stimulus for the itch by applying alcohol or pepper extract
may provoke an inhibitory feedback not supplied by scratching alone and lead to inhibition of the urge to scratch.
5
The phenomenon of hyper-
5
Itching
240
16. Perianal Dermatology and Pruritus Ani 241
TABLE 16-1. Differential diagnosis of anal dermatoses
Inflammatory disease Nonsexual infectious disease
Pruritus ani Pilonidal disease
Psoriasis Hidradenitis suppurativa
Lichen planus Fistula-in-ano
Lichen sclerosis et atrophicus Crohn’s disease
Atrophoderma Tuberculosis
Contact (allergic) dermatitis Actinomycosis
Seborrheic dermatitis Herpes zoster
Atopic dermatitis Vaccinia
Radiation dermatitis Fournier’s gangrene
Behçet’s syndrome Tinea cruris
Lupus erythematosus Candidiasis
Dermatomyositis “deep” mycoses
Scleroderma Amebiasis cutis
Erythema multiforme Trichomoniasis
Familial chronic pemphigus Schistosomiasis cutis
(Hailey-Hailey) Bilharziasis
Pemphigus vulgaris Oxyuris (pinworm)
Cicatricial pemphigoid Creeping eruption (larva migrans)
Sexually transmitted disease Premalignant and malignant disease
Gonorrhea Acanthosis nigricans
Syphilis Leukoplakia
Chancroid Mycosis fungoides
Granuloma inguinale Leukemia cutis
Lymphogranuloma venereum Basal cell carcinoma
Molluscum contagiosum Squamous cell carcinoma
Herpes simplex Melanoma
Condyloma acuminata Bowen’s disease (AIN)
Source: Modified from Corman.
Larva currens
Cimicosis (bed bugs)
Pediculosis (lice)
Scabies
Extramammary Paget’s disease
2
attending the healing of surgical wounds and scars probably
results from the combination of histamine release, release of
other kinins and prostaglandins involved in the inflammatory
phase of healing, and regeneration of nerves that may be
thinly myelinated in immature scars. Antihistamines, topical
anti-inflammatory agents (steroids), topical anesthetics, and
aloe preparations (prostaglandin inhibitors) all have beneficial
effects on the itching of healing wounds.
5
Etiology of Pruritus
Because pruritus is a symptom that may have protean causes,
it is useful to consider diagnoses that have been associated
with pruritus ani. Table 16-2 is a list of diagnoses and conditions modified from Stamos and Hicks.
considered below.
Localized Itch Syndromes
Notalgia paresthetica is a defined syndrome with itching or
pain of the upper mid back to either side of the scapular
region. This has been attributed to spinal nerve damage or
entrapment, but an inherited form with eight affected family
members has been described. Skin biopsies have shown
increases in sensory innervation in the area, and other changes
that could be attributed to repeated rubbing and scratching.
Treatment by application of pepper cream (capsaicin 0.025%)
has been effective. Such treatment may exacerbate the symptoms during the first week of application, but thereafter both
the symptoms and the side effects of the treatment subside.
Topical application of EMLA® (2.5% lignocaine + 2.5%
prilocaine), a topical anesthetic cream, has also been effec-
5
tive.
Dermographism has been reported as a cause of anogenital pruritus,
idiopathic form of pruritus ani may be a related disorder, and
that the skin changes are the sole result of skin trauma. The
effectiveness of the anal tattooing procedures, discussed later,
lends some support to this hypothesis.
7,8
It is not unreasonable to propose that the
6
Specific causes are
TABLE 16-2. Proposed etiologies of idiopathic pruritus ani
Anatomic factors Obesity, deep clefts, hirsutism, tight clothing
Anorectal disease Fissure, fistula, tags, prolapsing papilla, hemorrhoids, mucosal prolapse, sphincter insufficiency, deforming scars
Antibiotics
Contact dermatitis Chemicals in topical preparations, toilet paper, wet wipes, alcohol, witch hazel, “caine” anesthetics, fecal soiling
Dermatoses Psoriasis, seborrheic dermatitis, atopic dermatitis, lichen planus, lichen simplex, LS, dermographism
Diet Coffee (caffeinated and decaffeinated), chocolate, spicy foods, citrus fruits, tomatoes, beer, dairy products, vitamin A and D
Diarrhea Infectious diarrhea, irritable bowel syndrome, Crohn’s disease, ulcerative colitis
Drugs Quinidine, colchicine, intravenous steroids
Gynecologic conditions Pruritus vulvae, vaginal discharge of infection
Idiopathic
Infection Viruses: herpes simplex, cytomegalovirus, papillomavirus; bacteria: S. aureus, beta hemolytic strep, mixed infections; fungi:
Neoplasms Bowen’s disease (AIN), extramammary Paget’s disease, squamous cell carcinoma variants, secreting villous tumors
Personal hygiene Poor cleansing habits, over-meticulous cleansing producing mechanical trauma, use of soaps
Psychogenic/neurogenic Anxiety, neurosis, psychosis, neurodermatitis, neuropathy, “itch syndromes”
Radiation Radiation dermatitis, sphincter compromise or leakage caused by radiation proctitis
Systemic disease Jaundice, diabetes mellitus, chronic renal failure, iron deficiency, thyroid disorders, lymphoma, polycythemia vera
Source: Modified from Stamos and Hicks, 1998.
deficiencies, fat substitutes, consumption of large volumes of liquids
dermatophytes, Candida species; parasites: pinworms, scabies, pediculosis; spirochetes: syphilis
6
242 C.O. Finne
Fecal Contamination
Systematic, rigorous studies of anal pruritus are rare, but good
evidence supports fecal contamination as one cause of symptoms. Caplan
which fresh autologous feces was applied as a patch test both
perianally and on the inner arm, and perianal skin was also
cultured for fungi. There were 10 control subjects where feces
samples were collected; the skin was spatulated but feces not
applied to the skin. The patch-tested subjects had several pHadjusted samples applied to the skin in addition to the unadulterated samples. Twelve of the 27 had a history of pruritus ani.
pH of the perianal skin varied from 5.0 to 7.0 and was not different between the two groups. Five of 12 pruritus subjects
(42%) grew yeast (non–Candida albicans) but no dermatophytes, whereas 4 of 15 nonpruritus subjects (27%) grew
C. albicans (3) or Geotrichum. Twelve of 27 (44%) with feces
applied to the skin developed symptoms from the feces. Four
of 12 (33%) of the pruritus group developed symptoms, 8 of
15 (53%) of the nonpruritus group developed symptoms,
whereas none of the control group developed symptoms.
Symptoms occurred within 1–6 hours in all but one subject
and were relieved by washing the skin. Only one of the 27
subjects reacted to feces on the arms patch test, suggesting
that the skin in different locations reacts differently. The
prompt appearance of symptoms and relief with cleansing
was believed to indicate an irritant effect rather than an
allergic effect.
Smith and colleagues
with pruritus found that half of their patients had poorly
formed stools and 41% of their patients complained of soiling
from daily to several times a week. Seepage of liquid and
mucous was believed to be an important factor in the etiology
of the symptoms. Coffee was demonstrated to lower anal
resting pressure in 8 of 11 patients.
Allan et al.
test occurred sooner in patients with pruritus ani than in nonpruritic controls (median leak point 600 mL versus 1300 mL
in controls). This is consistent with findings by Farouk et al.
and Eyers and Thomson13who both found that the anal
inhibitory reflex was more pronounced in patients with pruritus ani. Rectal distension, because the decrease in anal pressure from baseline is greater in patients with pruritus ani,
makes these patients more prone to leak and soil.
9
performed a study in 27 Caucasian men in
10
in a rigorous study of 75 patients
11
showed that leakage during a saline infusion
12
rupture, ulcerate, and may become secondarily infected.
Culture or biopsy shows specific diagnostic findings.
Likewise, molluscum contagiosum produces characteristic
lesions, papular, 2- to 5-mm diameter, with central umbilication, usually clustered. Human immunodeficiency virus–
associated lesions are rarely associated with chronic itching
except for secondary fungal infections. No credible evidence
exists for a viral etiology in idiopathic pruritus ani.
Fungal Infection
Smith et al.10found no instances of fungal infection in their
investigation of pruritus in which each of 75 patients had
scrapings and fungus cultures. In contrast, Dodi et al.
14
found
C. albicans had no relationship to pruritus (culture positive in
23% of control subjects, 26% of those with pruritus, and 28%
of those without pruritus), but 10 patients who cultured dermatophytes all had itching. None of these patients had exposure to steroids or antibiotics. Their conclusion was that
C. albicans was saprophytic in the absence of steroids, but
that dermatophytes were always pathogenic. Prolonged
courses of steroids are said to enhance pathogenicity of
C. albicans and to mask Candida infection.
15
Verbov3found 7 of 47 patients (15%) with pruritus ani
whose itching was attributed to Candida out of a review of his
dermatologic practice (3000 patients surveyed on the basis of
their primary complaint). Pirone et al.
16
claim that surgical
treatment of anal disorders (hemorrhoids, fissure, spasm,
mucosal prolapse) eliminated Candida and dermatophyte
infections in all but 3 of 23 patients who were culture positive
and symptomatic with itching before surgery. Two of these
three failures responded to antifungal treatment, but the final
patient continued to itch.
In another study of 200 patients evaluated by colorectal surgeons and dermatologists, thrush was found in 28 (14%), only
one of whom was diabetic. Fourteen patients had local steroid
therapy, and 6 occurred after a course of systemic antibiotics.
Only one case of dermatophyte infection was found.
17
Perianal dermatophyte infection, all Trichophyton rubrum,
was reported to be infrequent by Alexander
15
(4 of nearly 300
cases). Topical steroids may render direct scrapings negative
for hyphae.
Bacterial Infection
Viral Infection
Condylomata acuminata are a common cause of itching, but
the diagnosis is easily recognizable and should not be confused with idiopathic pruritus ani. Condylomata, papilloma
virus infection, and anal intraepithelial neoplasia (AIN) will
be discussed extensively elsewhere. Herpes syndromes are
usually accompanied by pain rather than itching and the
clinical course is accompanied by a characteristic eruption
consisting of red macules, which progress to vesicles that
Several non–sexually transmitted bacterial infections are
reported to cause longstanding pruritus. Weismann et al.
17A
reported that 19 patients (16 males and 3 females) with pruritus of duration 1–20 years had beta hemolytic streptococci
cultured (four also had Staphylococcus aureus) from the perianal area but not from nasal or throat swabs. Treatment with
various regimens resulted in cure of 42% and amelioration of
symptoms in the others.
Erythrasma was reported to cause pruritus in 15 of
81 patients (18%) who had failed to respond to routine
16. Perianal Dermatology and Pruritus Ani 243
treatment.18Wood’s light fluorescence (coral pink) was the
most reliable diagnostic maneuver, being positive in every case,
but cultures of Corynebacterium minutissimum were positive in
only four cases. Groin, thighs, and toes were also involved in
every case and cure was achieved in all patients with erythromycin. Smith et al.
10
found erythrasma in only 1 of their
75 patients, each of whom had Wood’s light examination.
C. minutissimum is probably present in normal skin flora, but the
moisture, diabetes, and obesity predispose to infection which is
usually found in the body folds (axilla, groin, intergluteal, inframammary) and toe webs.
19
The St. Mark’s series found erythrasma in 16% of their 200 cases, but 27% of the group were
symptomatic for more than 5 years.
17
Their patients had disease
in more than one site, in common with other quoted series.
S. aureus has been anecdotally implicated as a cause of
treatable pruritus.
Mark’s series and was highly treatable with topical agents.
20
Intertrigo was reported in 27% of the St.
17
Contact Dermatitis
Contact dermatitis has been reported from a wide variety of
preparations including topical anesthetics, topical antibiotics,
topical antiseptics, topical antihistamines, and nickel.
Common sensitizing agents identified in the dermatologic literature are listed in Table 16-3. The role of feces and seepage
as a contact agent has been emphasized in almost every article
devoted to pruritus ani. Contact dermatitis may have an irritant
or allergic basis, but is recognized by being an eczematous
inflammation characterized by erythema, scale, and vesicles.
Avoidance of contact with the inciting agent is the obvious
treatment, and topical steroids may be useful unless secondary
infection is present. It is preferable to avoid soaps. Bath oils
and emollient creams may be useful for cleansing. The cause
of contact dermatitis may be obscure. Dasan et al.
one patient who had pruritus associated with bathing in a
tub of water in which his wife shampooed her hair with
para phenyl diamine, a dye. When the patient’s wife stopped
shampooing her hair in the tub, his symptoms resolved.
A large study of patch testing in 80 patients with pruritus
ani in Sheffield, England, emphasized the importance of
TABLE 16-3. Common sensitizing agents
Ethylenediaminetetraacetic acid
Formalin
Lanolin (wood wax alcohol)
Mercury
Neomycin
Nickel
Paraben mixtures
Paraphenylenediamine
Potassium dichromate
Rubber ingredients
Topical anesthetics
Turpentine oil
)Cl, thimerosal]
[Hg(NH
2
(benzocaine, dibucaine)
21
reported
17,21
contact dermatitis as an aggravating factor. Fifty-five patients
tested positive. Thirty-eight of the positives were to medicaments or their constituents including neomycin, fragrance
mix, Peru balsam, and cinchocaine. After counseling, twothirds of these 55 patients experienced improvement or reso-
23
lution of their symptoms.
These authors disputed the
recommendation to use “wet wipes” for cleansing because of
possible sensitization. Bruynzeel
24
corroborates the potential
sensitization from use of moist wipes containing methyldibromoglutaronitrile. Rohde believes that excessive exposure to
water and the act of excessive cleansing itself may incite
symptoms, and recommends the use of oils for cleaning.
Alexander
15
found lanolin, neomycin, procaine, and
parabens to be offending agents and emphasized the difficulty
of identifying these types of products when incorporated with
a local anesthetic or steroid because the anesthetic suppresses
the itching and the steroid suppresses the inflammation giving
paradoxical temporary relief. Temporary relief leads to
increasing application of the offending agent over a wider
area, escalating the process.
15
Psoriasis
Psoriasis has been an important underlying cause of pruritus in
every series on this subject. In a combined colorectal dermatologic clinic established to prospectively evaluate patients with
pruritus, 22 of 40 patients were found to have psoriasis.
Alexander15confirms that psoriasis may present as an isolated
22
lesion in the perianal area, and emphasizes that lesions in this
location do not appear as typical because of maceration. Smith
10
et al.
found 6 cases (8%) of psoriasis in his series, 5 of which
had not been previously diagnosed. The St. Marks-Guy’s hospital series found 5.5% of their 200 patients had psoriasis.
They also emphasized the nontypical appearance of the perianal lesions. Lochridge
25
claimed the diagnosis of perianal
psoriasis in 81 patients, all of whom responded to fluocinolone
acetonide 0.025% (Synalar ®) with normalization of the skin.
He recommended a search for lesions elsewhere including
elbows, knees, ankles, extensor surfaces of the forearm, base
of the scalp, ear canals, eyelids, nipples, penis, vulva, or navel.
Biopsy was rarely diagnostic because of secondary changes
as a result of drugs or trauma and limited experience of
pathologists with diagnosis of perianal skin.
Lichen Sclerosis
Lichen sclerosis (formerly lichen sclerosus et atrophicus)
(LS) is a chronic disease of unknown cause, almost always
occurring in women (female/male 10:1, usually seen on the
penis in the male) which in females has a predilection for the
vulva and perianal area. The skin has a characteristic appearance that is white, atrophic, and wrinkled.
of the labia gives this condition a characteristic distribution
that makes recognition easy once the diagnosis is considered.
Biopsy is characteristic and may be especially indicated in
22,26–29
Involvement
21
17
244 C.O. Finne
a lesion not responding to treatment because of rare occurrence
of squamous cell carcinoma.
30–32
Treatment of LS with a
potent topical steroid (clobetasol propionate 0.05%,
Temovate®) for 6–8 weeks is highly successful, often resulting in normalization of the skin.
5,27,29
Other recent reports
suggest that tacrolimus ointment may avoid the skin atrophy
that may accompany potent steroid use.
33,34
Patients with LS
in the vulva probably have a 4%–5% incidence of squamous
cell carcinoma arising in or adjacent to the LS.
31
These
patients should be followed periodically for raised lesions or
ulcers that fail to heal. The exact role LS has in the development of cancer is not certain, but is thought to be independent
of human papilloma virus.
30
Food Factors
No controlled trials have been done to examine food stuffs or
diet as a cause for itching, but strong opinions have garnered
a revered place in the literature. Friend
35
states that virtually
all patients with idiopathic pruritus ani consume enormous
quantities of liquids, are almost never constipated, and usually
have loose stools. Because it helps their symptoms, patients
with severe pruritus usually maintain good anal hygiene.
Friend states that there are six common foods that unequivocally cause idiopathic pruritus: coffee, tea, cola, beer, chocolate, and tomato (ketchup) and that total elimination will
result in remission of itching in 2 weeks. After a 2-week elimination period, the food may be reintroduced to determine the
threshold above which consumption causes symptoms.
Thresholds are typically between 2–3 cups of coffee, 4 cups
of tea, and less than 2 cans of beer.
Smith et al.
10
demonstrated that coffee lowered anal resting
pressure in 8 of 11 patients tested. An elimination diet gave
partial or complete relief in 27 of 56 (48%) of their patients.
Specific dietary items identified by elimination as a cause
were coffee (8), alcohol (5), peanuts (3), chocolate (2), milk
products (3), cola (1), and citrus (1). Alcohol was an equivocal factor in this study because 41% did not consume alcohol
and only a third of patients drank more than 1 ounce per day.
Smith et al. confirm the importance of poorly formed stool
and coffee which may contribute to seepage and recommend
a bulk agent taken at the same time of day to promote regular,
complete emptying of stool.
Daniel et al.
1
reported that average coffee intake in patients
with primary pruritus ani averaged 6 cups per day, compared
with those with secondary pruritus who averaged about
3.5 cups per day.
36
Akl
reported an 8-year-old boy with asthma, intolerant of
milk with abdominal pain, whose pruritus ani disappeared
after elimination of yogurt.
Coexisting Anal Disease
Coexisting surgical anal conditions (hemorrhoids, fissure, fistulas) may of themselves produce itching or aggravate any
tendency to itch. Most authors agree that correcting these
disorders in selected patients is indicated. Smith et al. reported
that 8 of his 75 patients required treatment of hemorrhoids
(four operations, four Barron ligations) which by virtue of
10
prolapse may induce soiling.
These authors note, however,
that correction of the hemorrhoids eliminated itching in only
one patient. Another with scars from previous fissure surgery
also had soiling not amenable to surgical correction. Murie
37
et al.,
in a study of 82 hemorrhoidal patients with and without pruritus, believe that pruritus is more common in patients
with hemorrhoids than in age- and sex-matched controls without hemorrhoids and that correction of the hemorrhoids
usually eliminates itching along with the other symptoms of
bleeding, pain, soiling, and protrusion. Bowyer and McColl
reported that hemorrhoids were the sole cause of itching in 16
of their 200 patients, contributory in 27 others, and that
correction of fissure was required in five patients before
symptoms were relieved. Five others had skin tags which
when removed eliminated symptoms. These patients could
point to the skin tag as the source of the itching. Dasan et al.
in a study of 40 patients with pruritus found two that required
surgery, one to remove complex skin tags and the other to
correct a fistula. The St. Louis University group found that
52% of 109 patients with the sole presenting complaint of
itching had anorectal disease as the cause.
1
The diagnoses
included hemorrhoids, fissure, idiopathic proctitis, condyloma, ulcerative proctitis, abscess, and fistula.
Pirone et al.,
16
as mentioned above, believe that correction
of hemorrhoids, fissure, mucosal prolapse, and spasm can
resolve fungal infection and the consequent pruritus.
Psychologic Factors
Smith et al.10studied 25 of their patients who completed an
MMPI (Minnesota Multiphasic Personality Inventory). They
found no deviations on the clinical scales but a trend toward
inhibition of aggression, and denial of feeling of social and
emotional alienation. Anxiety, stress, and fatigue added to
personality, coping skills, and obsessive compulsive disorders
probably have a role in the exacerbation of pruritus ani.
Because of this, psychiatric drugs may have a role in its management in isolated cases, but the preponderance of evidence
suggests, in my opinion, that idiopathic pruritus ani does not
have a psychiatric basis except as a form of neurodermatitis.
The fact that it responds to simple topical treatment with resolution of physical findings in most cases and is so common
argues against an obscure etiology.
Steroid-induced Itching
Anogenital itching has been reported after bolus administration of intravenous dexamethasone.
occurs as a rebound phenomenon after withdrawal of steroids
leading to their reinstitution and chronic use because symptoms always exacerbate after withdrawal. This syndrome has
39
More often, itching
17
21
38
16. Perianal Dermatology and Pruritus Ani 245
been characterized as steroid addiction40and can lead to per-
41
manent deformity and dependence.
Experimental application of potent steroids under occlusion for as little as 3 weeks
has been shown to produce an acute dermatitis resembling
that seen with a blister that has been unroofed and exposed to
40
air.
In my view, steroids should always be viewed as potentially dangerous and should be used to achieve specific
effects. Potency and dosing should be tapered in a planned
manner with the goal of eliminating steroids altogether from
a maintenance regimen. If elimination is not possible, alternate day therapy or intermittent therapy once or twice a week
is to be preferred.
Skin Trauma
Trauma can arise from physiologic processes such as diarrhea
or frequent stools which may be associated with frequent wiping and maceration. Scratching either consciously or nocturnally while asleep may result in the classic lesion of lichen
simplex chronicus. Alexander-Williams
42
puts it nicely:
“Perianal dermatitis is a cross between a nappy rash, athlete’s
foot, and a self inflicted injury. In most patients the problem is
due either to inadequate cleansing of the anus or to over vigorous attempts to polish it clean.” There is controversy about the
best way to clean the anus. Rohde
43
takes issue with the standard method using water or wet wipes and advocates a smooth,
dry article with olive oil if necessary, believing that water
breaks down the barrier function of the skin. Most authors
agree that contact dermatitis is a contributing cause of perianal
irritation and that attempts to discontinue over-the-counter
preparations (OTCs), perfumed, or scented products including
toilet paper, should be made because of potential sensitizing
agents (Table 16-3). Bland emollients, Acid Mantle®-based
creams, and waterless cleansing agents are reasonable substitutes that may be used with tissue paper or cotton balls for
cleansing and left on the skin. My own experience suggests that
dilute white vinegar (1 tablespoon in 8 ounces of water) and
Burow’s solution (Domeboro®) are effective cleansing agents
associated with little adverse reaction. Burow’s solution and
acetic acid have been found to be an effective antibacterial in
chronic otitis with little toxicity.
44–47
Neoplasms
Perianal Paget’s disease is rare and large series do not exist,
but more than half of patients in most series have itching,
often for longer than 3 months.
ease (intraepithelial squamous cell carcinoma in situ) is also
rare, but in a series of 47 patients reviewed at the Cleveland
Clinic, 28 (60%) had perianal itching as a presenting com-
51
plaint.
AIN is the sequel to human papillomavirus infection (associated with itching) and refers to premalignant
change in the area of the dentate line and anal transitional
zone. Although pruritus has not been described in large
series looking at AIN
52,53
48–50
Perianal Bowen’s dis-
(because of their study design), it
would seem prudent to be alert for neoplastic change in any
patient with a history of warts who presents with pruritus.
Higher-grade tumors such as melanoma or squamous cell
cancer usually present with bleeding or pain, not with pruri-
54–56
tus.
Further discussion of anal neoplastic disease is
found in Chapter 35.
Diagnosis of Perianal Disease
Given the variety of possible diagnoses as cataloged so far, it
is important to identify the specific diagnoses that are treatable for cure, and to engage a strategy that will avoid mistakes. It is often helpful in the differential diagnosis of anal
and perianal disease processes to divide them into the general
classifications of mass (inflammatory or neoplastic), rash, or
fissure (primary or secondary). The morphology of a lesion is
a starting point for diagnosis, but may not be specific, and the
same disease may have several different appearances (Table
16-4). As an example, candidiasis may be present as an erythematous lesion, a papular lesion, or as an ulcerative lesion.
Specific techniques are necessary, therefore, to establish or
eliminate a diagnosis. Bacterial culture is a time-honored
technique for identification of organisms, but proper media
and collection techniques must be used to avoid killing certain
species.
TABLE 16-4. Morphology of perianal skin lesions
Ulcers Papules
Diffuse erythema Crusts
Miscellaneous findings
57
Herpes genitalis Venereal warts
Syphilis Scabies
Trauma Molluscum contagiosum
Chancroid Candidiasis
Fixed drug eruption Syphilis
Lymphogranuloma venereum
Tularemia
Behçet’s syndrome
Malignancy
Donovanosis (granuloma inguinale)
Candidiasis
Histoplasmosis
Mycobacterioses
Amebiasis
Gonorrhea
Trichomoniasis
Candidiasis Herpes genitalis
Trauma Scabies
Contact dermatitis
Fixed drug eruption
Linear tracks: scabies
Reddish flecks: crab louse excreta
Maculae ceruleae (sky-blue spots): crab lice
Nits: crab lice
Hypertrophic: donovanosis
246 C.O. Finne
History and Physical Examination
History and physical examination, often overlooked in our
technologic arrogance, is still the most basic maneuver for
diagnosis of any disease (see Table 16-5). Inquiry about other
skin diseases, allergic conditions such as asthma or urticaria,
or sites of involvement may be the first clue to diagnosis of
unrecognized psoriasis or atopic dermatitis. Patients may not
relate the itch on their elbow to the itch around their anus.
Erythrasma usually involves the groin and toes, usually is
chronic, and is often associated with hyperpigmentation.
Patients frequently do not consider OTC or nonprescription
preparations as medicines, but these may modify the appearance of a condition or even cause it. Specific questions about
the use of these products are necessary to uncover their use
and exposure to unsuspected ingredients. Knowledge of a
patient’s allergies is important not only for avoidance, but
may aid in uncovering an unsuspected exposure to an occult
ingredient. Patients sometimes have had patch testing and
allergy consultation, and will not volunteer that information
unless specifically asked. Patch testing, dermatologic consultation, and withdrawal of medication may be in order.
Specific questions about infections, colds, or diarrheal illnesses treated with pills may be necessary to uncover antibiotic use. Patients sometimes will not list prednisone in their
list of medications until asked a question pertinent to an illness such as arthritis or asthma or myalgias. A condition that
has come and gone for years or that has seasonal exacerbation
may be a clue to anal fissure, but could reflect dietary
changes, type of clothes worn, or laundry practices.
Physical examination should specifically look for other
sites of involvement. The groin is a classic intertriginous area
that is easily accessible in the prone jackknife or the lateral
position and should be the first place one looks to confirm a
suspected yeast or fungus diagnosis. Hyperpigmentation in
the buttock cleft or other intertriginous area is a clue to a
chronic inflammatory condition or the presence of chronically
infected drainage or secretion. Effective treatment of a patient
with changes in the groin as well as the cleft requires attention to each area of involvement. If a condition is infectious,
steps to eliminate the infection will be more successful if the
environment of the host is made inhospitable to the organism
in each area of involvement. A sharply defined border usually
points to a definable diagnosis such as tinea, especially when
accompanied by scale (Figure 16-1). Psoriasis usually has a
sharply defined border, but in the cleft may lack the classic
scale seen in skin that is exposed to air. In the confined,
occluded area of the cleft, there usually is no scale (Figure
16-2). Neoplastic changes may appear sharply marginated, but
margins may be microscopically involved, especially around
the dentate line, even if grossly normal (Figure 16-3, Bowen’s
disease). Infiltrative processes may be less well defined as in
Paget’s disease of the anus with the same caveat about margins (Figure 16-4). Inflammatory changes of idiopathic nature
often have borders that are indistinct and nondescript (Figures
16-5 and 16-6). Bright red erythema often is seen with perianal yeast (Figure 16-6). Erythema may be seen with chronic
steroid use (Figure 16-7). Patient A had used hydrocortisone
daily for 20 years or more and came in with recurrent warts
and carcinoma in situ when the cortisone failed to control his
symptoms. Treatment of his warts, carcinoma in situ, and
withdrawal of his steroids resulted in resolution of his symptoms and normalization of his skin. Patient B had used
Mycolog® cream daily for several years, having had radiation
therapy for prostate cancer. He was also treated with withdrawal of steroids. Acute severe injury from prolonged diarrhea with frequent wiping produced the picture of lichen
simplex chronicus (Figure 16-8), which was treated by specific treatment of the patient’s diarrhea, cleansing with
Burow’s solution, and topical silver sulfadiazine to which
T
ABLE 16-5. Historical and physical factors aiding diagnosis of anal
and perianal disease
Historical
Other skin conditions, asthma, urticaria
Prior treatments/OTC topicals
Allergies
Chemicals/clothes/laundry
Antibiotic use
Systemic disease
Chronicity
Physical findings
Multiple sites (elbows, groins, intertriginous areas, labia, toe webs)
Mass or woody induration
Hyperpigmentation
Scale
Lichenification
Ulceration
Groin adenopathy
Defined edge or margin
FIGURE 16-1. Dermatophyte infection. Note the sharp border, the scale
at the edges, and its involvement of the groin crease. As this type of
infection moves into the anal cleft, the characteristic edge at the border of the cleft and involvement of the groin may be the only clues.
16. Perianal Dermatology and Pruritus Ani 247
FIGURE 16-2. Psoriasis often appears atypical in the cleft and
around the labia, lacking the silvery scale that is so characteristic.
Isolated areas of involvement in the cleft occur and require biopsy
confirmation by a competent skin pathologist.
FIGURE 16-4. Perianal Paget’s disease may present as a nondescript
rash that itches. This clinical appearance is not specific and requires
biopsy to confirm the diagnosis. Unlike Paget’s of the breast, there is
rarely an underlying invasive adenocarcinoma, and local excision
with clear margins is the treatment of choice. Margins of excision
require frozen section confirmation because clinically normal skin
may be involved.
cortisone was added. Chronic infected discharge may lead to
hyperpigmentation in the cleft (Figure 16-9) in this case
caused by chronic pilonidal disease, but may also occur with
fistulas, chronic yeast or fungus infection, or hidradenitis.
Treatment complications can result in a rash in this patient
with a contact dermatitis from clotrimazole (Figure 16-10).
Severe symptoms, especially paresthesias, coupled with scattered lesions may be a clue to herpes virus infection (Figure
16-11). LS characteristically involves the perineum and labia
in the female and has a distinctive appearance with wrinkling
of the skin (Figure 16-12). Biopsy is characteristic.
Groin adenopathy, and whether or not the nodes are tender,
can have specific relevance to diagnosis of perianal and anal
disease (Table 16-6), especially sexually transmitted disease.
Laboratory Examination
FIGURE 16-3. Anal Bowen’s disease or squamous cell carcinoma
in situ may have a varied appearance and be indistinguishable from
Paget’s Disease (Figure 5) by clinical examination. The white pearls
on the red background are often present and are a clue to the
diagnosis. Despite sharp-appearing edges, the process often involves
normal-looking skin and requires frozen section to confirm negative
margins.
Ideally, infected material should be aspirated with a syringe
and expelled into a sterile container. Next best is a swab of
exudate collected from a deep portion of the lesion. Bacterial
and fungal cultures should be placed into a bacterial transport
medium and refrigerated if any delay in transport to the laboratory occurs. Anaerobic specimens require transport in a special anaerobic medium, and should not be refrigerated. Viral
248 C.O. Finne
cultures require a viral transport medium and should be kept
on ice. Vesicular lesions should be unroofed and cultures
taken from the base of the vesicle. Microscope slides can be
pressed against the base of the lesion for Tzanck smears, but
inoculation of the fluid or exudate from the lesion base onto
cell culture is more sensitive (viral culture).
57
The office should have arrangements with a laboratory,
which will supply culture swabs with transport media appropriate for aerobic, anaerobic, fungal, and viral culture. These
become outdated and can result in rejection of specimens for
processing. The practitioner should check the appropriateness
of the media and its date before using it. Because staph and
strep have been documented as causal agents, it is prudent to
culture for pathogens in almost all cases in which treatment is
not obvious. Conventional water-soluble lubricant is bactericidal for some organisms (Neisseria gonorrhoeae). Swabs
should be lubricated with saline if lubricated at all. Ulcerated
lesions should have the base vigorously swabbed. Biopsy
should be accomplished early with a representative lesion and
should include an area of adjacent normal skin. Specific query
should be made to the pathologist about suspected diagnoses,
and if possible a pathologist with skin expertise should be
consulted. Highly reliable histologic criteria exist for viral
lesions, pyoderma, syphilis, and neoplastic lesions. EMLA®
cream, applied as a lubricant at the time of examination, may
FIGURE 16-5. Classic severe pruritus ani is marked by lichenification
(leathery thickening of the skin), accentuation of folds, fissuring of
the skin, and erosions and an indistinct border. Changes this severe
require short-term aggressive therapy with high-potency steroids for
4–8 weeks which then are rapidly tapered to a maintenance program,
if possible without steroids. It is important to rule out secondary
infection, which requires specific treatment.
facilitate injection of local anesthetic, and biopsy may conveniently be done with either an 11 blade or skin punch blades
that come in numerous sizes in separate sterile packages
(Figure 16-13). Bleeding from punch biopsy holes is readily
controlled with sliver nitrate sticks or GELFOAM® packing.
FIGURE 16-6. Perianal yeast may present as a bright red rash without the cheesy exudate sometimes seen elsewhere and may follow treatment
with antibiotics for some other condition. This infection is easy to treat but has a tendency to recur. Rendering the cleft environment inhospitable
by drying with a hair dryer after bathing and using athletes foot powder to coat the skin and absorb moisture can help maintain remission.
FIGURE 16-7. Chronic steroid use may cause itching or mask other processes. A An elderly man who had used 1% cortisone daily for more
than 20 years, but had worsening of his symptoms despite increasing use. Treatment of his warts and carcinoma in situ along with withdrawal
of steroids resolved his symptoms. The erythema has disappeared and he had remained free of symptoms for over a year. B A similar erythema superimposed on radiation dermatitis from treatment of prostate cancer. Withdrawal of Mycolog®, which had been used for years
without interruption and substitution of a barrier cream with menthol relieved his symptoms.
FIGURE 16-8. This man has classic lichen simplex chronicus with
inflammation and erosion resulting from unremitting diarrhea of 3
weeks’ duration with wiping five times a day. Treatment of the
patient’s diarrhea and topical silver sulfadiazine with 2% cortisone
achieved rapid healing and relief of symptoms.
FIGURE 16-9. Hyperpigmentation may result from chronic inflammatory changes in the skin for whatever reason. In this particular
case, infected drainage from a chronic pilonidal sinus was the cause,
but fistula disease, chronic dermatophyte infection, erythrasma may
produce the same picture. This finding should emphasize the need to
modify environmental conditions within the cleft and surrounding
area as an adjunct to healing.
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