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TABLE 12.8.2 Most Common Causes of Polymyalgia
Polymyalgia
rheumatica (1–4) Fibromyalgia (5)
Inflammatory conditions
(e.g., polymyositis/
DM) (6)
Epidemiology
Most common >50 y
Middle age, usually
<50 y
Most common 40–60 y
2:1 women:men
58/100,000 (1)
Affects women more
than men 2–8%
(where studied)
2:1 women:men
1/100,000
Pathophysiology Cause unknown
Systemic inflamma-
tion commonly
found in proximal
joints surrounding
tendons, bursa,
and soft tissues
Large vessel vasculitis
Unclear
Sensitization of central
nervous system
Inflammation of striated
muscle
DM, also involves skin
History Sudden onset
>2 wk duration
Systemic: fever,
malaise, anorexia,
weight loss,
depression
Specific: proximal
symmetric
shoulder and/or hip
girdle pain with AM
stiffness (lasting
>45 min)
Chronic widespread
Nonarticular pain and
muscle tenderness
Systemic: fatigue,
sleep disturbance,
headaches,
frequently multiple
symptoms
Slowly progressive
Systemic: fever, malaise,
weight loss
Specific: proximal
symmetric muscle
and truncal weakness
over weeks to months
(worse after use)
Dysphagia (50%)
Physical Proximal tenderness
(bilateral) upper
arms and thighs,
limited range of
motion in neck,
shoulders, and hips
secondary to pain
Tender “trigger”
points (11 of 18
points)
No weakness
Proximal tenderness
AND weakness
( bilateral)
Muscle atrophy
Rash (DM), Gottron’s
papules, heliotrophe
rash on eyelids
NO weakness
Laboratory tests
Elevated ESR >50
mm/h (often ESR
100 mm/h)
Normochromic
normocytic anemia
No specific test
Normal ESR
ESR
Creatine kinase
Aldolase
Autoantibodies: anti-Jo-1
Electromyography
Muscle biopsy
(Continued)
288
Taylor’s DifferenTial Diagnosis Manual
3. Is there a significant past medical history? Ask about medications and family history. In
the social history, it is important to inquire about occupation and sources of stress.
B. Physical Examination. Pay particular attention to the musculoskeletal system. Inspect
for muscle atrophy and palpate for muscle tenderness (including the scalp and temporal
artery). The presence or absence of muscle weakness is the key clinical finding. Even patients
with significant pain can perform a brief maneuver at maximum effort to assess strength.
Distinguish between soft tissue pain (myalgia) and joint pain (arthralgia). Are the tender
points located in a significant pattern (fibromyalgia)? Is a rash present?
C. Testing. Frequently, laboratory tests fail to elucidate the cause. Baseline investigations may
include a complete blood count, erythrocyte sedimentation rate, C-reactive protein, glucose,
liver function tests, creatine kinase, thyroid function tests, electrolytes, rheumatoid factor,
urinalysis, and a chest radiograph. If muscle weakness is present, consider obtaining serum
aldolase, anti-Jo-1 antibodies, electromyelogram, and/or muscle biopsy. Consideration may
be given to obtaining serologies for infectious diseases, depending on risk factors (1).
IV. DIAGNOSIS. The differential diagnosis is wide ranging (Table 12.8.1). It is important to
review the patient’s history and perform a complete physical examination to most accurately
delineate the cause of polymyalgia.
TABLE 12.8.2 Most Common Causes of Polymyalgia
Polymyalgia
rheumatica (1–4) Fibromyalgia (5)
Inflammatory conditions
(e.g., polymyositis/
DM) (6)
Treatment Rapid response to
oral prednisone
(10–20 mg/d)
No response to
steroids
Multifaceted
individualized
program
Medications:
muscle relaxants,
antidepressants
Exercise
Admission, steroids,
cytotoxics
Splinting of joints and
gradual rehabilitation
Associations Temporal arteritis
(giant cell arteritis)
25/100,000 (1)
Symptoms: headache,
scalp pain, temporal
artery tenderness
(beading or
diminished pulse),
visual disturbance,
jaw or tongue
claudication
Irritable bowel
s yndrome
Sleep disorders
Restless leg syndrome
Depression/anxiety
Myofascial pain
syndrome
Chronic fatigue
syndrome
Systemic lupus
erythematosus,
rheumatoid arthritis,
systemic sclerosis
Malignancy (lung, ovary,
breast, stomach)
Extramuscular
manifestations:
cutaneous (DM),
cardiac, pulmonary,
gastrointestinal
DM, dermatomyositis; ESR, erythrocyte sedimentation rate.
(Continued)
Chapter 12 • Musculoskeletal Problems
289
REFERENCES
1. Donnelly JA, Torregiani ST. Polymyalgia rheumatica and giant cell arteritis. Clin Fam Pract
2005;7(2):225–246.
2. Dasgupta B, Borg FA, Hassan-N, et al. BSR and BHPR guidelines for the management of polymyalgia
rheumatica Rheumatology 2010;49:186–190.
3. Spiera RF, Paget SA. Polymyalgia rheumatica and temporal arteritis. In: Goldman L, Schafer A, eds.
Goldman’s Cecil textbook of medicine, 24th ed. Pennsylvania, PA: Elsevier Saunders, 2011:1728–1731.
4. Unwin B, Willimas C, Gilliland W. Polymyalgia rheumatica and giant cell arteritis. Am Fam Physician
2006;74(9):1547–1554.
5. Chakrabary S, Zoorob R. Fibromyalgia. Am Fam Physician 2007;76(2):248–254.
6. Khan S, Christopher-Stine L. Polymyositis, dermatomyositis, and autoimmune necrotizing myopathy
clinical manifestations. Rheum Dis Clin North Am 2011;37:143–158.
7. Lyman D. Undiagnosed vitamin D deficiency in the hospitalized patient. Am Fam Physician
2005;71(2):299–304.
12.9
Shoulder Pain
Kevin J. Benson
I. BACKGROUND. Shoulder pain is a common musculoskeletal complaint. Eighty-five percent
of patients with pain have a problem that is intrinsic to the shoulder. Understanding the func-
tional anatomy and biomechanic properties will help determine the etiology and appropriate
treatment (1).
II. PATHOPHYSIOLOGY
A.
Pathologic processes cannot be evaluated in isolation because of the complex relationship
of the shoulder girdle with other structures. The shoulder is composed of three bones
(clavicle, scapula, and proximal humerus) and four articular surfaces (sternoclavicular (SC),
acromioclavicular (AC), glenohumeral (GH), and scapulothoracic (ST)). The GH joint is
loosely constrained by muscles and ligaments within a thin capsule. The rotator cuff (RC)
is composed of four muscles (supraspinatus, infraspinatus, subscapularis, and teres minor),
which serve as a dynamic stabilizer. The function of the subacromial bursa is to lubricate
and protect the RC tendons from the pressure and friction of the underside of the acromion.
Shoulder motion is dependent on the AC and SC joints and the ST articulation. Repetitive
overhead activities, trauma, or instability can result in impingement, which is associated
with pain and inflammation.
B. Younger patients, especially those who participate in sports requiring overhead motion, have
pain and instability secondary to repetitive microtrauma of the labrocapsular structures.
Psychosocial factors may play a role in chronic pain. Focal degeneration and ischemia of
the RC occurs with advancing age. Other sites of significant pain due to trauma include the
biceps tendon, AC joint, and brachial plexus. Pain can be referred from the cervical spine,
chest, and abdomen to the shoulder.
III. EVALUATION
A. History.
Pain should be described accurately (onset, duration, palliation, provocation,
quality, location, and radiation). Inquire about previous injuries, past surgery, and other
comorbidities. A fall on an outstretched hand (FOOSH) can give rise to instability in a
younger patient and RC tear in the elderly. A fall on the point of the shoulder may result
in an RC tear or AC joint injury. Throwing injuries stress the labrocapsular complex and
ligamentous attachments and give rise to RC tendonitis and bicipital tendonitis. Referred
pain may arise from other sources like myocardial ischemia, hepatobiliary disease, and nerve
entrapments.
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Taylor’s DifferenTial Diagnosis Manual
B. Physical Exam. It should be guided by history and approached in a step-wise fashion. Is
it traumatic versus nontraumatic, extrinsic versus intrinsic, GH versus extra-GH? Inspection
should include all aspects of the shoulder. Palpation should reveal tenderness, swelling, or
instability. Range of motion should be both active and passive. Check abduction, adduction,
flexion, extension, and internal and external rotation. See special tests to confirm shoulder
pathology as noted in Table 12.9.1 (2). The sensitivity and specificity of these tests is ques-
tionable (1).
1. GH pathology is unlikely in the presence of normal range of passive motion. There are
tests for impingement (Neer and Hawkin’s sign), RC pathology (empty can test, lift-off
test, and drop arm test), AC joint pathology (cross-body adduction test), biceps tendon
injury (Yergason and Speed’s tests), and instability (apprehension test).
2. The painful arc (pain with abduction between 60° and 120°) suggests impingement (3).
3. Limited active abduction associated with weakness against resistance suggests an RC tear.
TABLE 12.9.1 Special Tests to Confirm Shoulder Pathology
Test Maneuver Pathology
Neer test
(impingement sign)
Examiner stabilizes patients acromion with
one hand, performs maximum passive
shoulder abduction and internal rotation
with the other.
Subacromial inflammation,
impingement
Hawkin’s
impingement sign
Forced internal rotation with the shoulder
flexed forward to 90°
Impingement
Jobe’s test (empty
can test)
Deltoid assessed with arm at 90° abduction
and neutral rotation. Shoulder then
internally rotated and angled forward
30°; thumbs pointing toward the floor.
Downward pressure of examiner’s hand
resisted.
Supraspinatus weakness
due to injury, pain due
to rotator cuff pathology
Cross-body adduction
test
Shoulder flexed to 90° and adducted
across the patient’s body
Rotator cuff/acromiocla-
vicular pathology
Lift-off test Patient’s arm behind back, with volar
surface of the hand resting on the
sacrum. Weakness in lifting the hand
away from the spine
Subscapularis muscle
weakness/injury
Yergason test Supination of the pronated forearm against
resistance with the elbow flexed at 90°
Biceps tendonitis/tear
Speed’s test Extension and supination of the elbow
as the examiner resists flexion of the
humerus
Biceps tendonitis/tear
Apprehension test Abduction to 90° and external rotation of
the shoulder with the examiner’s hand
applying forward pressure to the scapula.
The patient resists further shoulder
extension
Positive anterior instability
Drop arm test The arm is passively abducted to 90° and
the support is suddenly discontinued. A
positive test is reported if the arm drops
abruptly
Rotator cuff tear or axillary
nerve injury
Chapter 12 • Musculoskeletal Problems
291
4. AC joint pathology is accompanied by pain on top of the shoulder, localized tenderness,
and possible pain referral to the neck.
5. Crepitus is associated with GH osteoarthritis.
C. Testing
1. Lab Tests. A CBC and synovial fluid analysis for cell count, Gram stain, and culture
are obtained if infection is suspected. Consider checking erythrocyte sedimentation rate,
C-reactive protein (CRP), antinuclear antibody (ANA), and joint aspirate for crystals in
an inflammatory process.
2. Imaging Studies. There are no specific guidelines. Plain radiography including anterior–
posterior, lateral, and scapular views may be beneficial if there is loss of range of motion,
severe pain, or known trauma. The following may be identified: fracture of the proximal
humerus, clavicle, and scapula, GH dislocation, AC joint pathology, and SC joint
pathology (requires apical lordotic view of chest). Magnetic resonance imaging (MRI) is
preferred with suspected impingement and RC injury. If it is normal, there is less than a
10% chance of a tear. MRI is useful in the evaluation of avascular necrosis, biceps ten-
dinopathy or rupture, and inflammatory processes. Ultrasound is helpful in identifying
RC tear, labral tear, and biceps tendon tears and dislocation. MR arthrography can be
useful in evaluating and treating frozen shoulder (4). Computerized tomography (CT)
scan may be an option if there is a contraindication to using MRI (5). CT is preferred
for imaging tumors and occult fractures. CT arthrography may play a role in suspected
RC tears in patients with claustrophobia (4).
IV. DIAGNOSIS
A. Specific Conditions
1. Subacromial bursitis is a term used when describing the pathology of impingement. It
is usually associated with RC tendonitis.
2. RC tendonitis has three stages (edema and hemorrhage of tendon, fibrosis of subacro-
mial bursa, eventual rupture of tendon if not responsive to treatment). Fifty percent of
patients over age 70 years have RC tears. RC tears may eventually lead to cuff arthropa-
thy (5).
3. Bicipital tendonitis is associated with overuse and commonly occurs in weight lifters.
Rupture of the long head of the biceps (Popeye sign) is often present. Weakness is sel-
dom significant, since 85% of the power associated with elbow flexion comes from the
short head of the biceps and brachioradialis (3).
4. Adhesive capsulitis is a painful restriction of shoulder movement of soft tissue ori-
gin. It is associated with diabetes, thyroid disease, pulmonary disorders, stroke, and
Dupuytren’s disease. The diagnosis is clinical (6).
5. AC syndromes can be acute or chronic and are usually posttraumatic in the young. AC
osteoarthritis usually follows AC separation or excessive repetitive training. It is common
after age 40 years.
6. Calcific tendonitis. Calcification occurs as part of a degenerative process of the RC
tendons. It usually occurs in the fourth decade. Twenty-one percent have complete RC
tears associated with it. The condition is associated with HLA-A1 (1).
7. ST bursitis. This condition is often seen among patients with habitually poor posture.
Crepitus is usually present at the superior medial angle of the scapula.
8. GH instability represents a spectrum of disorders from unidirectional dislocation to
multidirectional instability. It could be from repetitive overhead activity, FOOSH, or
anterior dislocation of the shoulder. It usually occurs in athletes.
9. Polymyalgia rheumatica is seen in older patients who have pain and stiffness in both
shoulders. The sedimentation rate (and more commonly CRP level) is elevated in these
patients.
10. Temporal arteritis may present with shoulder pain associated with headache and visual
changes or jaw claudication.
11. Fibromyalgia, cervical radiculopathy, and thoracic outlet syndrome are also common
sources of shoulder pain (4). If the pain radiates below the elbow and possibly into the
hand, consider a source of pain extrinsic to the shoulder.
292
Taylor’s DifferenTial Diagnosis Manual
REFERENCES
1. Dalton SE. The shoulder. In: Hochberg MC, Silman AJ, Smolen JS, Weinblatt ME, Weisman MH,
eds. Rheumatology, 5th ed. Philadelphia, PA: Mosby Elsevier, 2011:683–699.
2. Ramakrishnan K, Jones AD. Shoulder pain. In: Paulman, ed. Taylor’s 10-minute diagnosis manual, 3rd
ed. Philadelphia, PA: Lippincott Williams and Wilkins, 2077:292–295.
3. Waldman SD. Physical diagnosis of pain: an atlas of signs and symptoms. Philadelphia, PA: Elsevier
Saunders, 2006.
4. Burbank KM, Stevenson JH, Czarnecki GR, Dorfman J. Chronic shoulder pain. Am Fam Physician
2008;77(4):453–460.
5. Anderson BC, Anderson RJ. Evaluation of the patient with shoulder complaints, 2012. Retrieved from
http://www.uptodate.com
6. Ewald A. Adhesive capsulitis: a review. Am Fam Physician 2011;83(4):417–422.
Chapter 12 • Musculoskeletal Problems
293
CHAPTER 13
Dermatologic Problems
Hassan Galadari
13.1
I. BACKGROUND. Hair-related problems are common medical complaints encountered by phy-
sicians. Among the most common problems presenting to the primary care provider are telogen
effluvium and androgenic alopecia (1).
The human scalp has an average of 100,000 hairs (2). The hair follicle goes through three
stages of growth. The initial growth phase, a process that lasts an average of 2–6 years, is termed
the anagen phase (2). At any one time, 90–95% of scalp hair is in the anagen phase. This is
followed by the catagen phase, which is a transitional stage, in which the hair follicle enters a
process of involution (2). This stage lasts for 2–3 weeks. Less than 1% of scalp hair is in the
catagen phase (2). Approximately 5% of hair follicles enter a resting stage, at the end of which
they are shed. This process may last 2–3 months and is known as the telogen phase (2).
II. PATHOPHYSIOLOGY
A. Etiology.
Alopecia can be classified by its clinical presentation, that is, according to
whether the alopecia is localized or generalized. Alternatively, the classification can be based
on the pathology of the condition causing the alopecia. This classification divides alopecia
into scarring (cicatricial) and nonscarring (noncicatricial) alopecia (3). In scarring alopecia,
hair loss occurs due to inflammation, leading to permanent follicular damage (2). Scarring
alopecia generally causes localized hair loss. Examples of scarring alopecia include infections
such as severe folliculitis, dissecting cellulitis, and kerion; inflammatory disorders affecting
the hair follicle and scalp such as discoid lupus erythematosus, lichen planopilaris, and
bullous diseases; other disorders such as tumors, acne keloidalis, frontal fibrosing alopecia,
and pseudopelade of Brocq (2). In nonscarring alopecia, the hair loss is not permanent and
regrowth is generally possible after treatment. Examples of nonscarring alopecia include
telogen effluvium, androgenetic alopecia, anagen effluvium, alopecia areata, and traumatic
or chemical alopecia (3). Telogen effluvium is the most common cause of diffuse hair loss
(3). It occurs after a stressful event such as surgery, childbirth, crash dieting, or psychological
illness (4). It often occurs 3 months following the inciting event and resolves spontaneously
after 3–4 months (4). Anagen effluvium involves loss of anagen hair and usually occurs
10–24 days after starting chemotherapeutic agents (3). Androgenetic alopecia or male pat-
tern baldness occurs in genetically susceptible individuals in a process known as hair minia-
turization, resulting in shortened anagen phase and subsequently shorter, thinner hair shaft
(1). While both sexes may be affected by androgenetic alopecia, the condition is much more
commonly seen in men. Fifty percent of males over the age of 50 years will have some degree
of androgenetic alopecia. Alopecia areata is an autoimmune disorder affecting hair follicles,
resulting in nonscarring hair loss (3). The clinical picture varies from localized patches of
hair loss to total body involvement termed alopecia universalis (3). Chemical and physical
Alopecia
Khawla Rashid Alnuaimi and Hassan Galadari
294
trauma to hair follicles secondary to the use of hot combs, hair straighteners, and traction
may occur (2). Prolonged or repeated trauma to the hair follicle may permanently damage
the hair follicles, resulting in scarring alopecia (2).
B. Epidemiology. Alopecia is a common problem affecting all genders, all races, and all ages.
A variety of illnesses result in alopecia, each with its own distinct age, sex, and race charac-
teristics and patterns of morbidity. The most common causes of alopecia are androgenetic
alopecia and telogen effluvium (1).
III. EVALUATION
A. History.
To assess patients with hair loss, a careful medical history and examination can
help avoid expensive, unnecessary evaluation, and laboratory tests. In the history, physi-
cians should inquire about onset and duration of hair loss, any preceding stressful event,
medications, and diet. In the review of systems, physicians should ask specifically for thyroid
symptoms. Family history of hair loss, androgenetic alopecia, and autoimmune disorders
should be determined (2).
B. Physical Examination. Examine the scalp and hair shaft carefully. Determine whether
the hair loss is diffuse or localized, look for signs of inflammation, and determine hair
density. The texture, length, and thickness of individual hairs may suggest the cause of hair
loss. Shorter, fine hairs may be found in areas affected by androgenic alopecia. “Exclamation
point hairs,” which have a distal broken shaft and a proximal club-shaped hair root, are seen
at the periphery of hair loss in alopecia areata (5). Short, broken hairs in the area of hair
loss are seen with trichotillomania and tinea capitis. All areas of the body must be carefully
examined for hair growth patterns and changes. Trichotillomania can be seen in the scalp,
eyebrow areas, and even the eyelashes. Patterns of hair loss in male pattern androgenic alo-
pecia typically range from bitemporal recession, to frontal and vertex thinning, and to loss
of all hair except for the occipital and temporal fringes. Female pattern alopecia classically
presents as diffuse thinning that is more prominent in the frontal or parietal areas, with
sparing of the frontal fringe (5). In women, signs of virilization associated with androgenic
alopecia may be seen. Virilization can also cause acne, hypertrichosis in other areas, deepen-
ing of the voice, and clitoromegaly. Rashes or other changes in the skin either in the area of
hair loss or elsewhere may suggest various causes. Scaling and flaking suggest tinea, psoriasis,
or drying of the skin as a result of heat or chemicals. Scarring of the areas of hair loss suggest
trauma, infection, or discoid lupus. A “moth-eaten” pattern of hair loss on either the scalp or
face should suggest syphilis and sarcoid or discoid lupus. Telogen effluvium can be detected
by the “pull test,” which is performed by grasping approximately 60 hairs between thumb
and fingers and exerting traction to determine degree of shedding and anagen to telogen hair
ratio (2). Normal shedding should yield six or fewer hairs. The patients’ hair should not have
been shampooed in the 24 hours prior to this test (6).
C. Testing
1. Any laboratory testing should be ordered on the basis of clinical findings. A typical
androgenic alopecia pattern of hair loss with normal skin in men and women without
evidence of virilization requires no further testing. Women who show evidence of
virilization should have serum free testosterone, total testosterone, prolactin, and dehy-
droepiandrosterone sulfate levels drawn first. If these are abnormal, then workup should
continue, focused on the specific findings. Patients with nonandrogenic patterns of
alopecia should have thyroid function tests, a complete blood count, a ferritin level, and
an antinuclear antibody done. The need for syphilis serology should also be considered
on the basis of the history and examination. If these tests are all normal, other nutritional
deficiencies, such as zinc, may be considered (7). Bacterial and fungal cultures of any
drainage should be obtained. Potassium hydroxide microscopic evaluation of skin scrap-
ings for fungal elements and/or fungal cultures of scaling areas can confirm the diagnosis
of fungal infection.
2. Scalp biopsy for histopathology may be useful in suspected cases of scarring alopecia for
definitive diagnosis (5).
295
D. Genetics. Inherited or congenital hair disorders affecting the scalp and hair can result
in structural defects with or without hair fragility (4). There are more than 300 genetic
disorders that affect the hair (8).
IV. DIAGNOSIS
A. Differential Diagnosis.
The key consideration in diagnosis is whether the hair loss is
localized or generalized or scarring versus nonscarring. Subsequent examinations as noted
earlier allow a definitive diagnosis.
B. Clinical Manifestations. Most cases of alopecia are caused by either androgenic alopecia
or telogen effluvium. Early diagnosis and intervention can be critical in the remaining cases
if caused by thyroid disorder, carcinoma, metastatic adenocarcinoma, melanoma, syphilis, or
human immunodeficiency virus. Permanent hair loss may be prevented or limited by early
institution of therapy. If alopecia is caused by a drug, hair loss can be reversible if the drug
is stopped early in the process. Treatment, if desired, for androgenic alopecia works best if
started early on in hair loss.
REFERENCES
1. Beth G, Adam O. Androgenetic alopecia. www.Uptodate.com. Accessed July 21, 2012.
2. Habif T. Clinical dermatology, 5th ed. Philadelphia, PA: Elsevier, 2010:916–938.
3. Bth G, Adam O. Nonscarring alopecia. www.Uptodate.com. Accessed July 21, 2012.,
4. Anthony D. Atlas of clinical dermatology. Philadelphia, PA: Elsevier, 2002:631–634.
5. James WD, Berger TG, Elston D. Andrew’s diseases of clinical dermatology. Philadelphia, PA: Elsevier,
2006:749.
6. Bertolino A. Alopecia areata. Postgrad Med 2000;107(7):81–90.
7. Irvine A, Christiano A. Hair on a gene string: recent advances in understanding the molecular genetics
of hair loss. Clin Exp Dermatol 2001;26:59–71.
8. Thiedke C. Alopecia in women. Am Fam Physician 2003;67(5):1017–1018.
13.2
I. BACKGROUND. Erythema multiforme (EM) and related diseases are a group of mucocutane-
ous disorders believed to be a hypersensitivity reaction triggered by various stimuli, including
infectious agents and drugs (1–4). The clinical classification of this group of diseases is com-
plicated partly due to controversies regarding the precise etiologies of some of the conditions
and the clinical manifestation of the disease along a spectrum. However, EM broadly consists
of the syndromes EM minor, EM major (EMM), Stevens-Johnson syndrome (SJS), and toxic
epidermal necrolysis (TEN) (Table 13.2.1). EM minor represents the mild end of the spectrum,
presenting as an acute self-limiting eruption. It is primarily confined to acral sites, with mini-
mal to no mucosal involvement. In contrast, EMM, SJS, and TEN are more serious diseases,
with associated morbidity and/or mortality. EMM is characterized by more extensive mucosal
involvement as compared with EM minor. SJS and TEN are considered to represent a single
disease entity distinguished only by the severity of the illness. Both are also considered to be
related to EMM.
II. PATHOPHYSIOLOGY
A. Etiology.
EM minor, EMM, SJS, and TEN are believed to be hypersensitivity reactions
triggered by various stimuli. These include infectious agents and drugs (1–4). Recent her-
petic infections (herpes simplex virus, HSV 1 and 2) are the most common triggers of EM
minor and EMM; recent work implicates transport of viral particles to the skin by CD34
cells (5). Other infectious agents may also trigger EM. These include Epstein-Barr virus,
Erythema Multiforme
Amr Salam and Ophelia E. Dadzie
296
cytomegalovirus, Mycoplasma pneumonia (especially in children), mycobacterium tubercu-
losis (TB), β-hemolytic streptococcus, Histoplasma capsulatum, and Coccidioides immitis (3).
Drugs may also trigger EM minor and EMM; however, this accounts for a minority of cases.
In contrast, medications are a major trigger for the development of SJS/TEN. These
include allopurinol, carbamazepine, cotrimoxazole (and other anti-infective sulfonamides
and sulfasalazine), lamotrigine, nevirapine, nonsteroidal anti-inflammatory drugs (especially
oxicams), phenobarbital, and phenytoin (4). Drug-related illness appears to invoke a path-
way that involves tumor necrosis factor, whereas HSV-related illness does not (6).
B. Epidemiology. EM minor, EMM, SJS, and TEN occur worldwide, in individuals of all
ages, although most are under 40 years old (2–4). Significant ethnic variation in the inci-
dence of SJS/TEN has been observed (7).
III. EVALUATION
A. History.
Pertinent aspects of the clinical history which must be obtained include the pres-
ence of prodromal symptoms, any concurrent or preceding illness, and recent drug exposure
(2, 4). EM minor is often asymptomatic, although some patients may experience itching
or tenderness. The condition is of sudden onset and generally does not cause systemic
symptoms. Herpetic infection is an important etiologic factor in the setting of EM minor
and EMM; thus, the history should specifically explore the presence or absence of recent
infection. In SJS/TEN, prodromal symptoms may occur. These include fever, malaise, and
myalgias. Recent exposure to medications (especially in the preceding 1–3 weeks) is of rel-
evance in the setting of SJS/TEN.
Table 13.2.1 Overview of EM and Related Diseases
Condition Defining Features
EM minor
Typical target lesions (≥3 zones), mainly cutaneous (acral sites), rarely
involves mucous membrane but if so usually mouth only
infective triggers > drug triggers
BSA <10%
EMM
skin lesions as with EM + ≥2 mucosal sites, may have associated
infectivetriggers > drug triggers
BSA <10% (but more severe than EM)
SJS Atypical target lesions (2 zones), purpuric macules on face and trunk,
severe mucosal erosions, systemic symptoms
drug triggers > infective triggers
BSA <10% (but more severe than EMM)
SJS/TEN overlap As with SJS
drug triggers > infective triggers
BSA = 10–30%
TEN Poorly defined erythematous macules and atypical target lesions
Early mucosal erosion, detachment of epidermis, systemic symptoms
drug triggers > infective triggers
BSA >30%
BSA, body surface area; EM, erythema multiforme; EMM, erythema multiforme major; SJS, Stevens
Johnson syndrome; TEN, toxic epidermal necrolysis.
297