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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1443_Библиотеки_им_академика_М_И_Перельмана.pdf
253
R. Cohen, A. Windsor (eds.), Anus,
DOI 10.1007/978-1-84882-091-3_20, © Springer-Verlag London 2014
Introduction
Patients with conditions affecting the perianal
skin present to various clinics, from proctology
to sexual health to general practice. The boundar-
ies of such specialties as dermatology, infectious
disease and gastrointestinal surgery are crossed
by the range of diagnoses that underlie com-
plaints in the perianal region. The problem may
be local to the anus, be an indication of intestinal
disease or represent a manifestation of a general-
ized dermatological disorder. In the latter case, it
is notable that the moist and warm environment
of the perianal region often produces differing
appearances to those characteristic of the disease
elsewhere.
The perianal region is a common site for pre-
sentation of sexually transmitted infections,
which are addressed in detail.
Perianal Anatomy and Function
The perianal skin is the circumferential area of
skin outside the anal verge, the border with the
anal canal. The anal canal develops embryologi-
cally from the posterior cloacal membrane which
unites hindgut and proctodeum by rupturing at 7
weeks’ gestation. Within it, a transition occurs in
cell type that refl ects the change from ectodermal
to endodermal origin. The perianal skin there-
fore, with the distal anus, derives from the proc-
todeum and is supplied by the pudendal vessels
with lymphatic drainage to the inguinal lymph
nodes. Sensation is somatic via the pudendal
nerve (S2, S3, S4), and the perianal area has its
own dermatome (S4) with an additional, poste-
rior area towards the coccyx supplied by S5, see
chapter.
Perianal skin has an inner circumferential area
closest to the anal verge with characteristic cor-
rugation brought about by the insertion of the
intersphincteric longitudinal fi bres into the der-
mis of the skin. This inner area of skin extends
approximately 10–15 mm from the anal verge –
equating to the diameter of the underlying exter-
nal anal sphincter [ 1 ]; it differs from the rest of
the perianal skin in three ways: it is more pig-
mented, it has only fi ne hairs and the corrugation
allows great stretch.
Microscopically, the structure of the perianal
skin is that of skin elsewhere. The perianal der-
mis is particularly adapted to stretch with many
thick elastin fi bres and is well supplied with
T. Cuming , MBBS, MEd, FRCS (Gen Surg) (*)
Department of Surgery, Homerton University
Hospital , London , UK
e-mail: tzcuming@gmail.com
A. C. Bailey , BM, BCh, MRCP (UK)
Jefferiss Wing Department of GU Medicine and HIV ,
Imperial College Healthcare NHS Trust,
St. Mary’s Hospital , London , UK
P. N. Sashidharan , BSc, MBBS,
DV, MD (Dermatology & Venereology),
MSc (Dermatology), Dip GUM, DFFP
Department of Sexual Health ,
Homerton University Hospital , London , UK
2 0
Perianal Skin Conditions
Tamzin Cuming , Angela C. Bailey ,
and Parameswaran N. Sashidharan
254
adnexa: the eccrine glands with sudomotor sym-
pathetic innervation, pilosebaceous units and
apocrine glands.
The dermal-epidermal border is bounded by
the basal layer of undifferentiated cells in an
undulating rete peg shape which produces kerati-
nocytes that mature and differentiate as they
move up through the three layers that constitute
the epidermis: the stratum spinosum, the stratum
granulosum and the stratum corneum.
The perianal skin thus comprises keratinized,
stratifi ed squamous epithelium with plentiful
skin appendages and is exquisitely sensitive to
pain. At the anal verge, the skin changes to the
non-keratinized, stratifi ed squamous epithelium
without skin appendages, but still with somatic
innervation and sensitivity to pain, which contin-
ues proximally until the transition zone within
the anal canal (see Anatomy chapter ).
Normal Flora
The perianal skin is an intertriginous (fl exural)
area with apposition of skin surfaces where
warmth and moisture encourage the proliferation
of bacteria and fungi to a high level. The anal
continence mechanism normally prevents mucus
and faeces from constantly bathing the perianal
skin; however, there is regular exposure to gas-
trointestinal as well as skin fl ora. The potential
pathogens Staphylococcus aureus and Candida
species are common commensals as is
Staphylococcus epidermidis of skin origin and
Bacteroides species, Enterococcus faecalis , and
Enterobacteriaceae of the lower gastrointestinal
tract. Fungal colonization with Candida albicans
is commonly asymptomatic [ 2 ].
Dermatology for the Proctologist
Terminology
Dermatological terminology is employed to
describe the appearance skin changes in a stan-
dardized and structured manner (see Table 20.1 ).
History
With a careful dermatological history (Box 20.1 )
and where relevant, a sexual history (Box 20.2 ),
a differential diagnosis can often be deduced
with clinical assessment alone (Table 20.2 ).
Table 20.1 Dermatological terms
Some commonly used dermatological terms
Macule – a fl at skin lesion <5 mm in diameter
Patch – a fl at skin lesion >5 mm in diameter
Papule – a raised skin lesion <5 mm in diameter
Plaque – a raised skin lesion >5 mm in diameter
Nodule – a solid raised skin lesion that extends into the
dermis or subcutaneous tissue
Erosion – partial loss of the epidermis
Ulcer – full-thickness loss of the epidermis
Vesicle – a fl uid-fi lled blister <5 mm in diameter
Bulla – a fl uid-fi lled blister >5 mm in diameter
Pustule – a pus-fi lled blister
Xerosis– dry skin
Telangiectasia – permanent dilation of small blood
vessels in the skin
Koebnerization – appearance of rash/lesions of the
same morphology at sites of trauma
Lichenifi cation – thickening of the skin due to repeated
rubbing
Box 20.1 Dermatological History
Presenting symptoms
Itching – especially at night
Bleeding
Pain/soreness (e.g. on defecation, constant/
intermittent, generalized/localized sharp/dull)
Lumps (e.g. warts)
Concerns of patients re symptoms (especially
anxiety and embarrassment)
Past medical history, for example, Crohn’s
disease, atopy and HIV
Family history of skin disease, for example,
psoriasis and atopic dermatitis
Drug history including topical medication
General habits including use of soaps, shower
gel, baby wipes and deodorants
T. Cuming et al.
255
Box 20.2 Tips on Taking a Sexual History
Be relaxed and ask questions as you would
normally
Be non-judgmental
Prepare:
Request that accompanying persons leave for
a moment
Explain to the patient that you need to ask
some personal questions about their sex life
as it may be related to their symptoms
Reassure them that the information will be
kept confi dential
Obtain permission to proceed
Suggested
questions:
Why ask this?
1. When was the last
time you had sex?
Find out if sexually active
and open conversation
(a) Was that a
regular partner or
a casual partner?
Gives an idea about risk
taking
(b) Was the
partner male or
female?
Ascertain sexual
orientation; risk of STIs
(c) Is the patient
or the partner from
another country?
Risk assessment for STIs
(d) With a
condom?
Risk taking behaviour
2. When did you last
have sex with a
different person
Rate of partner change is
an important risk factor
for STIs
Clarify details as
above
3. Have they ever
had anal sex?
Important risk factor for
perianal STIs
If so, was a condom
used?
4. For men: have
you ever had sex
with a man?
This may affect risk of
HIV, hepatitis B, even if
long ago
5. Have you ever
injected drugs or
had a blood
transfusion
(especially in a
developing
country or many
years ago)?
Risk for blood-borne
viruses
In all sexually active or intravenous drug-using
(past or present) persons, a blood-borne virus (HIV,
hepatitis B and C) and syphilis screen should be
offered. Ask if they have been previously tested
and if so when and what the results were
Table 20.2 Differential diagnoses
The multifactorial nature of perianal complaints can
combine to produce a large differential diagnosis for
any particular symptom. This box is a guide to possible
diagnoses to consider
White patches
Vitiligo
Lichen sclerosus
AIN (see premalignant conditions)
Lichen simplex
Red lesions
Dermatitis/eczema
Atopic
Contact
Irritant/chemical
Allergic
Seborrhoeic
Psoriasis
Infection – bacterial or fungal
Vascular tumours, e.g. hemangioma
Fissures of the skin
Crohn’s (multiple, ± anal canal fi ssure)
Psoriasis
Dermatitis
Herpes simplex virus (HSV)
Itching – see Pruritus Ani Chap.
21
Ulcer
Herpes (HSV)
Lymphogranuloma venereum (LGV)
Human immunodefi ciency virus (HIV)
Malignancy (see Malignant Disease)
Crohn’s disease
Varicella zoster
Cytomegalovirus (CMV)
Nicorandil
Behçet’s disease
Trauma/factitious
Deep mycoses
Chancroid
Donovanosis (granuloma inguinale)
Blistering disorders
Vesicles
Varicella including varicella-zoster virus
Herpes simplex
Stevens-Johnson syndrome
Bullae
Pemphigus vulgaris
Bullous drug eruption, e.g. fi xed drug eruption
(continued)
20 Perianal Skin Conditions
256
Examination
After inspection of the genital and perianal areas,
digital and speculum examination of the vagina
and sigmoidoscopy of the rectum should be con-
sidered. Examination of the scalp, oral cavity, hair
and nails and wider cutaneous examination can
then be targeted according to the fi ndings, for
example, the extensor surfaces of limbs in psoriasis
and oral cavity for lesions in secondary syphilis.
Diagnosis
The perianal skin is an accessible site for tissue
sampling if a diagnosis has not been arrived at
using clinical assessment. Skin scrapings (for
microscopy and culture), swabs and biopsy are
the mainstays of investigation.
For the proctologist, it is important to consider
viral swabs for herpes simplex virus as these are
often not part of the normal surgical management
(see later in this chapter).
Treatment
Simple treatments, such as the use of emollients
as soap substitutes, moisturizers and barrier
creams to protect the skin are highly effective
general measures in the management of many
skin conditions. These agents are particularly use-
ful in the management of dry skin, pruritus , pso-
riasis and irritant and atopic dermatitis (eczema).
Local anaesthetics have a role in painful disor-
ders such as fi ssure in ano and fi rst episode of
herpes simplex virus infection (HSV) and are
generally well tolerated, although contact derma-
titis has been described [ 3 ].
Antihistamines are used orally for pruritic
lesions.
Antimicrobial agents have an important role.
Many of these agents possess anti-infl ammatory
activity and are used to treat both infectious and
non-infectious skin disease, for example, the use
of tetracycline in hidradenitis suppurativa.
Antifungals are used in managing dermatophy-
tosis (ring worm), candidiasis (thrush), subcutaneous
and systemic fungal infections and in controlling
malassezia yeasts in seborrhoeic dermatitis.
Topical corticosteroids are the mainstay of the
management of allergic and infl ammatory der-
matological conditions. There are low, intermedi-
ate and high potency topical steroid preparations.
Weak preparations can be bought over the coun-
ter (Box 20.3 ).
Chronic use of potent topical corticosteroids
can lead to atrophy and telangiectasia. Therefore, it
is preferable that long-term management of patients
requiring such agents be carried out under medical
supervision. With purely perianal use, topical ste-
roids result in insignifi cant systemic absorption.
Steroid-sparing agents include calcineurin
inhibitors (e.g. pimecrolimus, tacrolimus). They
should be used with caution and with specialist
medical advice due to concerns regarding possi-
ble carcinogenic effects with long-term use.
Tumour necrosis factor (TNF) alpha inhibitor
drugs (e.g. infl iximab, adalimumab) are effective
in Crohn’s disease [ 4 ], and there is limited evi-
dence for their use in hidradenitis suppurativa [ 5 ].
Other treatment options include imiquimod,
retinoids and laser. Surgical management is nec-
essary for abscesses, biopsy and excision.
Sexual Health for the Proctologist
Sexually transmitted infections (STIs) frequently
involve the perianal area. Sexual practices involv-
ing the anus are common: anal intercourse in the
last year was reported by more than 10 % of UK
Lumps
Lipoma
Epidermoid cyst
Dermoid cyst/teratoma
Warts (condylomata acuminata)
Molluscum contagiosum
Condylomata lata
Seborrhoeic keratoses
AIN/bowenoid papulosis
Pseudofolliculitis (ingrowing hairs)
Prominent skin folds
Table 20.2 (continued)
T. Cuming et al.
257
adults and more than 20 % of US adults in house-
hold surveys [ 6 , 7 ]. Infections are discussed indi-
vidually, but the following principles apply to
management of all STIs:
1. Take a sexual history (see Box 20.2 ).
2. Confi rm the diagnosis in the laboratory if at
all possible. Ensure clinics and theatres are
supplied with the equipment for viral and
Chlamydia (nucleic acid amplifi cation tests –
NAATs) testing.
3. Treat diagnosed infections quickly (e.g. her-
pes simplex infection) or refer rapidly for
urgent treatment (e.g. for syphilis), recom-
mending sexual abstinence in the meantime.
Ensure local guidelines are followed.
4. STIs travel in packs – always screen for
other infections or recommend attendance
elsewhere for screening, including HIV, if you
suspect or diagnose one STI.
5. Management of STIs is not complete without
partner screening and treatment. Refer for
management of partners or at least ensure the
patient is aware that their partners are at risk.
6. STI diagnoses are associated with stigma and
psychological morbidity. Some patients may
require referral for specialist support.
Non-infectious Skin Disorders
Dermatitis (Eczema)
Dermatitis is a general term to describe infl am-
mation of the skin. It is often used synonymously
with eczema, a term that derives from the Greek
‘to boil’. It describes a group of diseases which
present with an itchy red rash that may show ooz-
ing, crusting or scaling.
Atopic Dermatitis (Atopic Eczema)
Atopic dermatitis/eczema is a pruritic eruption that
is recurrent, usually fl exural in adults, symmetrical
and associated with a predisposition to atopy (per-
sonal or family history of asthma, eczema or hay
fever). It can present in infancy, childhood or adult-
hood. Perianal involvement can rarely occur in all
three stages. The napkin area is usually spared in
infancy but can be affected [ 6 ]. Atopic dermatitis
accounts for 3–5 % of cases of pruritus ani in adults
[ 8 ]. Although atopic dermatitis is common, iso-
lated involvement of the perianal area is rare.
Treatment involves the use of antihistamines
to control itching and mild to moderately potent
topical corticosteroid preparations to control
infl ammation.
Contact Dermatitis
Contact dermatitis is a common underlying or
contributory cause of perianal symptoms and
Box 20.3 Topical Corticosteroid Preparation
Potencies
Mild :
Hydrocortisone 0.5 %; 1 %
With antifungals:
Hydrocortisone 1 % + clotrimazole 1 %
Hydrocortisone 1 % + miconazole 1 %
With antibacterials:
Hydrocortisone 1 % + fusidic acid 2 %
Moderate :
Clobetasone butyrate 0.05 %
With antimicrobials:
Clobetasone butyrate 0.05 % + oxytetracycline
3 % + nystatin 10,000 units/g
Potent :
Betamethasone valerate 0.1 %
Mometasone furoate 0.1 %
Hydrocortisone butyrate 0.1 %
With antimicrobials:
Betamethasone valerate 0.1 % + fusidic acid 2 %
Very potent :
Clobetasol propionate 0.05 %
Difl ucortolone valerate 0.3 %
Topical antibacterial preparation :
Fusidic acid 2 %
Mupirocin 2 %
Topical antifungal preparation :
Clotrimazole 1 %
Miconazole 2 %
Terbinafi ne 1 %
20 Perianal Skin Conditions
258
presents as an erythematous lesion representing a
reaction to a substance which has breached the
skin barrier [ 9 ].
Two forms of contact dermatitis are described
which can be diffi cult to distinguish clinically:
irritant contact dermatitis, where the cells are
directly damaged by the agent in question, and
allergic contact dermatitis, where such a sub-
stance induces a delayed-type hypersensitivity
reaction. Predisposing factors to this multifacto-
rial condition include atopic dermatitis, genetic
factors and environmental cofactors such as
moisture and occlusion [ 10 ].
Irritant Contact Dermatitis
This is caused by either exposure to weak irri-
tants (e.g. soap, shower gel) or contact with
strong irritants such as acids and alkalis and is a
nonimmune-mediated infl ammatory skin reac-
tion presenting in acute or chronic forms.
Symptoms include irritation and soreness or a
burning sensation. The skin usually appears ery-
thematous with vesicles in the acute stage with
scaling, fi ssures and lichenifi cation in the chronic
stage. Potential irritants in the perianal area
include hygiene products, wet wipes, detergents,
topical haemorrhoid preparations and products
for the relief of itching which can paradoxically
contain irritants as preservatives. Mucus and fae-
cal matter from incontinence, prolapse of haem-
orrhoids, or from the rectal mucosa lead directly
to irritant contact dermatitis, as it does in infants
(diaper/nappy rash).
Treatment involves withdrawal of the irritant
or protection against it with barrier creams along
with application of weak or moderately potent
topical corticosteroid cream or ointment.
Allergic Contact Dermatitis
Allergic contact dermatitis can be diffi cult to dis-
tinguish from irritant contact dermatitis. It is due
to a delayed hypersensitivity reaction (type IV)
[ 11 ]. An analysis of 1,168 suspected anogenital
contact dermatitis patients showed that allergy
was responsible in 25 %, with the main culprits
being the patient’s own products as well as lano-
lin and fragrances, and hence, these should be
used for allergen patch testing which is now
widely available [ 12 ]. Nail varnish allergy has
been described as a cause of perianal rash [ 13 ].
A preservative used in the increasingly popu-
lar moist toilet tissues/baby wipes (methylchlo-
roisothiazolinone/methylisothiazolinone, MCI/MI)
is known to cause allergic contact dermatitis [ 14 ].
Ingested allergens such as nickel [ 9 ] or spices in
food, particularly those related to balsam of Peru
(cinnamon, cloves, nutmeg, vanilla), can lead to
perianal dermatitis [ 15 ]. More commonly, how-
ever, allergic contact dermatitis is due to prepara-
tions intended to ameliorate anal symptoms:
haemorrhoid creams, deodorants and local anaes-
thetics [ 16 ]. Treatment involves identifying and
removing contact with the allergen to which the
patient is sensitized and use of mild to moder-
ately potent topical corticosteroid preparations to
control infl ammation.
Seborrhoeic Dermatitis (Seborrhoeic
Eczema, Cradle Cap)
Other affected sites: scalp, eyebrows, retroauric-
ular and genitocrural.
Seborrhoeic dermatitis is a chronic infl amma-
tory condition which can affect the perianal area.
It is relatively common (3–5 %) and more preva-
lent in men. It is characterized by pruritic ery-
thematous areas with greasy yellowish fi ne
scaling located in areas of high sebum produc-
tion, such as the scalp, back, groins, chest and the
genitocrural region. Scaling may be less obvious
in the perianal area, and examination of other
typical sites will give a clue to the diagnosis.
Seborrhoeic dermatitis is etiologically
associated with the yeast Malassezia furfur
( Pityrosporum ovale ), and the two ages of great-
est incidence – infantile (2 weeks to 12 months)
and adolescent-adult – correspond to periods of
increased sebum production. However, the rela-
tionship is not simple. Treatment involves con-
trolling seborrhoea of the scalp with antifungal
shampoos such as ketoconazole or zinc pyrithione
T. Cuming et al.
259
at the same time as low to intermediate potency
topical steroids in combination with antifungals
for the perianal skin lesions. Severe or treatment-
resistant seborrhoeic dermatitis may require oral
antifungals and is an indicator condition for
unrecognized human immunodefi ciency virus
(HIV) infection [ 17 ].
Secondary bacterial infection can occur, and
the differential diagnosis includes fl exural psori-
asis and intertrigo.
Lichen Simplex Chronicus (LSC)
This is a chronic eczematous condition character-
ized by localized plaques due to repeated rubbing
and scratching in response to pruritic stimuli. The
skin, initially erythematous, becomes lichenifi ed.
This leads to further itching which results in
habitual rubbing and more lichenifi cation, the
‘itch-scratch cycle’. Any area that can be conve-
niently reached can be affected including the
perianal area where lesions can be asymmetrical
(see Fig. 20.1 ). Precipitating factors include heat,
sweat, chemical irritation and ‘psychological’.
Twenty-fi ve percent of patients have a back-
ground of atopy [ 18 , 19 ].
LSC must be distinguished from psoriasis,
contact dermatitis and anal intraepithelial neopla-
sia (AIN). All causes of pruritus ani need to be
considered in the search for an underlying trigger,
including candidiasis, dermatophyte infection,
parasitic infestation as well as faecal inconti-
nence, haemorrhoids and neoplasia (see Chap.
21 ). Topical steroids are the mainstay of treat-
ment. Sedative antihistamines are helpful for con-
trolling pruritus at night. Other measures include
generic pruritus advice: avoiding soaps, using
cotton anal plugs and barrier creams. Patients
should be made aware that the rash will not
resolve until scratching and rubbing are stopped.
Psoriasis (Inverse Psoriasis,
Flexural Psoriasis)
Associated sites : extensor surfaces especially
elbows, knees, scalp and nails.
Psoriasis is a chronic infl ammatory disorder,
which, in its most common form, is characterized
by erythematous scaly papules and plaques typi-
cally seen over scalp and extensor surfaces of the
body. These are generally asymptomatic but
lesions occasionally can be pruritic.
Psoriasis affects 1–5 % of the population in
Western societies, with bimodal peaks in the
early 20s and mid-50s, with men and women
equally affected. There are several types of pso-
riasis, but the type seen in the perianal area is the
‘fl exural’ or ‘inverse’ type which also affects
axillae, popliteal fossae and inguinal and inter-
gluteal areas, as well as the inframammary area
in women.
Well-defi ned erythematous plaques or patches
with fi ssuring are seen which differ from psoria-
sis of non-intertriginous areas due to minimal
scaling (see Fig. 20.2 ). Genital and anal lesions
usually occur concomitantly. Although isolated
perianal psoriasis can rarely occur, other sites are
often affected and should be examined. Nail
changes include irregular pits, onycholysis (sepa-
ration of nail from the nail bed), subungual
hyperkeratosis (accumulation of keratin material
underneath the nail) and translucent yellowish
spots under the nail plate (oil drop sign).
Perianal psoriasis can mimic dermatitis, fun-
gal or bacterial infection due to the lack of char-
acteristic scaling at this site.
Fig. 20.1 Lichen simplex chronicus. Note lichenifi cation
over the perianal area especially on the left side (Courtesy
of Dr P N Sashidharan, Homerton University Hospital,
London)
20 Perianal Skin Conditions
260
Psoriasis may be the initial presentation of
HIV infection, or HIV can aggravate existing
psoriasis (see later in this chapter).
Treatment is with mild or moderately potent
topical steroids with or without antifungal agents.
Vitamin D analogues can be used as steroid-
sparing agents.
Lichen Sclerosus (Lichen Sclerosus
et Atrophicus and Balanitis Xerotic
Obliterans, LS)
Additional site: vulva.
Lichen sclerosus is a dermatological disorder
of unknown aetiology with predilection for the
anogenital region. There is a peak of incidence in
childhood. In adulthood, women are affected
more than men (10:1), usually at a postmeno-
pausal stage.
LS is considered an autoimmune disorder
with a similar profi le to vitiligo, morphea and
autoimmune disease of the thyroid [ 20 ].
It is characterized by ivory-white papules that
become confl uent to form whitish plaques that
subsequently become atrophic (see Fig. 20.3 ).
Keratotic follicular plugs may be seen on the sur-
face in early lesions. Focal areas of petechiae or
purpura may be seen in established lesions.
In women, involvement of the vulva and peri-
anal area simultaneously gives rise to a ‘fi gure
of eight’ or ‘hour glass’ appearance. Scarring
develops subsequently. Malignancy can occur in
3–4 % of cases of lichen sclerosus and needs to be
excluded if plaques or ulcerated lesions develop.
Biopsy helps to confi rm the diagnosis and
exclude premalignant and malignant changes.
The mainstay of treatment is potent topical steroid
creams. Long-term follow-up is recommended in
view of the potential for malignant change.
Lichen Planus (LP)
Additional sites: oral mucosa, trunk and nails.
Lichen planus is a chronic infl ammatory pru-
ritic mucocutaneous disease. The classic lesion is
an erythematous fl at-topped violaceous papule.
Whitish reticular lines can be seen on the surface
(Wickham’s striae). Koebner phenomenon can
occur with new lesions developing at sites of
injury. Whitish reticulated patches may be seen
in the oral cavity, and nail changes include longi-
tudinal ridging and pterygium (fusion of the nail
fold to the matrix).
There are several types of LP. The papular and
hypertrophic types can affect the natal cleft and
buttocks.
The erosive type of LP affects the anogenital
area and the oral cavity. It is painful due to the
desquamation, is chronic and is recalcitrant to
Fig. 20.2 Psoriasis. Well-defi ned erythematous plaque
with fi ssuring. Scaling is usually not a feature at fl exures.
(Courtesy of Dr P N Sashidharan, Homerton University
Hospital, London)
Fig. 20.3 Lichen sclerosus. Note whitish sclerotic area
over perineum extending to the perianal area and hypopig-
mented macules and papules confi ned to the rest of the
perianal area. The vulva was also affected (Courtesy of
Dr P N Sashidharan, Homerton University Hospital, London)
T. Cuming et al.
261
treatment. There is also a small (2–3 %) risk of
developing squamous cell carcinoma.
Lichen planus usually responds to potent topi-
cal steroids. Tacrolimus or pimecrolimus have
also been used with some success [ 21 ]. Refractory
cases may require oral immunosuppression. Late
presentation of erosive lichen planus can cause
adhesions and lead to stenosis of the introitus or,
rarely, of the anus.
Hidradenitis Suppurativa (Acne
Inversa, Verneuil’s Disease, HS)
Associated sites : inguinal, axillae, inframam-
mary and buttocks.
Hidradenitis suppurativa is defi ned as a
‘chronic, infl ammatory, recurrent, debilitating
skin disease’ [ 22 ]. It is a cause of chronic
abscesses and sinus formation in apocrine gland-
bearing areas of the skin – most commonly the
axillae, groins, perianal and buttock areas.
HS is extremely rare before puberty and more
common in women (3:1). Involvement of axil-
lary, groin and inframammary areas is seen more
in females, whereas the perianal region and but-
tocks are more affected in men. Around 25 %
have a familial form with an autosomal dominant
pattern [ 23 ].
The exact pathogenesis of HS is not known,
but it is thought to be due to occlusion of the pilo-
sebaceous- apocrine units which leads to rupture
of the follicle and an aseptic chronic infl amma-
tory process resulting in painful deep-seated red
nodules and sinus formation [ 22 ].
There is an association with other follicular
occlusion disorders leading to the concept of a
tetrad which also includes pilonidal sinus, acne
conglobata and dissecting cellulitis [ 24 ]. Other
predisposing factors include smoking, obesity
and altered sensitivity to hormones particularly
androgens although their infl uence has yet to be
fully elucidated [ 25 ].
The role of bacteria is debated: secondary
infection may occur; a primary causal role is not
established.
The clinical diagnostic hallmark is the pres-
ence of double or multiple comedones
(‘ tombstone’ comedones). The nodules do not
point which distinguishes them clinically from
bacterial furunculosis. The Hurley classifi cation
consists of three stages: stage one constitutes
abscess formation and is the most common type
(70 % of cases of HS); stage two involves sinus
formation and cicatrisation (25 %); and 1 % prog-
ress to stage three severe disease with diffuse-
bridged scarring and interconnecting tracts [ 26 ].
The differential diagnosis includes Crohn’s
disease, furunculosis, infected epidermoid cysts
and relatively rare infections such as tuberculo-
sis, lymphogranuloma venereum, nocardia and
actinomycosis.
Differential from cryptoglandular fi stulation is
usually made by inspection: HS is a superfi cial dis-
ease which although occasionally involving the
anal canal does not fi stulate across or within the
sphincters [ 27 ] (see Fistula-in-Ano chapter).
Despite this, the differential diagnosis can be diffi -
cult clinically and require both examination under
anaesthetic and MRI scan of the perineum to
exclude deep extension, as well as biopsy.
Diagnosis depends on the triad of features:
typical clinical appearance, typical sites and the
recurrent nature of the disease.
Conservative management includes general
measures such as reducing heat, humidity and
sweating with loose-fi tting undergarments, local
antiseptic washes, losing weight and stopping
smoking.
Antibiotics are used and may be needed long
term. The most effective are those with an anti-
infl ammatory function, such as the tetracyclines,
clindamycin and rifampicin. Modulation of the
sex hormones with anti-androgens is employed,
for example, with the use of oral contraceptives
containing cyproterone acetate. Retinoids also
have been used therapeutically as have corticoste-
roids, zinc gluconate [ 28 ] and topical resorcinol
treatment [ 29 ]. Nd: YAG laser therapy has found
a place [ 30 ]. The role of TNF-alpha inhibitors is
being explored: response in Hurley stage III can
be rapid with a dramatic effect [ 31 ]. Surgery is
used in three main ways: incision and drainage of
abscesses, deroofi ng and wide excision. Surgery
in combination with TNF-alpha inhibitors may be
required for severe disease (see Fig. 20.4 ).
20 Perianal Skin Conditions
262
Crohn’s Disease (Crohn’s Disease,
Terminal Ileitis)
Associated sites : ileum, colon, oral cavity and
extra-intestinal.
It is recognised that the gastrointestinal tract
from mouth to anus can be affected with the char-
acteristic full-thickness non-caseating granulo-
matous infl ammation of Crohn’s disease. There
are extra-intestinal manifestations such as the
rare cutaneous involvement with granulomatous
infl ammation (metastatic Crohn’s disease) as
well as more commonly associated joint, eye,
skin and hepatobiliary disorders.
Perianal Crohn’s disease represents a major
part of Crohn’s morbidity, with pain and inconti-
nence being common features. Perianal involve-
ment in Crohn’s disease is fairly common, with
25 % of those with terminal ileal and 75 % of
those with colonic Crohn’s affected, and the more
distal the affected Crohn’s segment, the more
likely the perianal involvement.
Crohn’s disease can affect ages from child-
hood onwards; however, it has a bimodal distri-
bution with a peak at age 20–40 years and a
second at ages 60–70 years. Crohn’s patients
with perianal disease present 8 years younger
than those without [ 32 ]; women are slightly
more likely to have an associated perianal diag-
nosis (57 %) [ 33 ]; perianal disease at an early
age is associated with a more severe course for
both luminal and perianal Crohn’s [ 32 , 34 ]. It is
a risk factor for proctectomy and stoma forma-
tion [ 33 , 35 ].
Perianal Crohn’s can predate the appearance
of Crohn’s disease elsewhere which it behoves
the clinician to consider [ 36 ] (see Fig. 20.5 ).
A number of scoring systems have been devel-
oped: the Cardiff and Perianal Crohn’s Disease
Activity Index being used mainly in research
[ 37 , 38 ]. Psychological morbidity of Crohn’s dis-
ease is disproportionately focused on the activity
of the perianal component of the disease [ 39 ].
Skin Tags
Skin tags are the most common perianal feature,
present in 40 % [ 37 ]. Unlike non-Crohn’s skin
tags, those due to Crohn’s can be painful. There
are two types of tag. Type 1 are infl ammatory in
ab
Fig. 20.4 Hidradenitis suppurativa: superfi cial fi stula-
tion and sinus tracts, ( a ) multiple fi stulae of perianal
hidradenitis suppurativa ( b ) probes in sinus tracks,
perianal hidradenitis suppurativa (Courtesy of Mr P A
Giordano, Whipps Cross University Hospital, London)
Fig. 20.5 Crohn’s disease of the perianal area without
fi stulation: skin tags and superfi cial fi ssuring (Courtesy of
Mr P A Giordano, Whipps Cross University Hospital,
London)
T. Cuming et al.