Rosen & Barkin's 5-Minute Emergency Medicine Consult (255 page)

Not contagious and does not require isolation or postexposure prophylaxis for exposed personnel

Generally benign and self-limited, requiring no initial stabilization

• Attempt to identify, treat, or remove underlying cause or precipitant.
  
• Symptomatic: Cool compresses, antipruritics
  

• Antiviral agents:
  
  • Acute EM
    
  • Treat within 48 hr of onset
    
  • May not impact clinical course
    
    • Acyclovir: 400 mg PO TID
      
• Prevention of recurrent EM
  
  • Acyclovir 400 mg PO BID
    
  • Valacyclovir 500 mg PO BID
    
  • Famciclovir 250 mg PO BID
    
• Antipruritic agents:
  
  • Cetirizine (Zyrtec): 10 mg/d (peds: 2.5–5 mg) PO
    
  • Diphenhydramine: 25–50 mg (peds: 5 mg/kg/24h) PO q6–8h
    
  • Hydroxyzine: 25 mg PO q6–8h (peds: 2 mg/kg/24h div. q6–8h)
    
• Anesthetic for oral lesions
  
  • Magic mouthwash
    
• Oral corticosteroids:
  
  • Reserved for severe mucosal disease
    
  • Prednisone 40–60 mg PO QD tapered over 2–3 wk
    
• Medium-potency topical corticosteroids:
  
  • Triamcinolone 1% apply BID–QID
    
    • Do not use on face or eyelids
      
• Low-potency topical corticosteroids
  
  • For face or intertriginous regions
    
  • Hydrocortisone 1% apply BID–QID
    

• Topical corticosteroids (low to medium potency)
  
• Antipruritics
  

• Antivirals
  
• Oral corticosteroids
  

FOLLOW-UP

• Admission is not needed unless required for another concurrent disorder.
  
• Unable to take PO fluids secondary to mucosal lesions
  

EM is generally a benign disorder that does not require admission.

• Patients should be referred to a dermatologist if the diagnosis is uncertain or the rash is atypical or severe.
  
• Refer immediately to ophthalmologist if ocular involvement
  

• Follow-up with primary care physician within 1 wk to assess:
  
  • Further evaluation of underlying conditions (infection, medications, malignancy, etc.)
    
  • Progression or resolution of rash
    
• Follow-up with a dermatologist within 1 wk if the diagnosis is uncertain.
  

• In patients with severe systemic illness, a more serious diagnosis should be considered, such as SJS or TEN.
  
• Most patients with EM have underlying HSV infection.
  
• Secondary syphilis may produce similar lesions on the palms and soles.
  
• Reassure patients that the rash of EM is benign and self-limited.
  

• Dyall-Smith D. Erythema multiforme. Available at
  www.dermnetnz.org
  . Accessed on July 1, 2011.
  
• Lamoreux MR, Sternbach MR, Hsu WT. Erythema multiforme.
  Am Fam Physician.
  2006;74:1883–1888.
  
• Plaza J. Erythema multiforme. Available at
  www.emedicine.com
  . Accessed on July 29, 2011.
  
• Scully C, Bagan J. Oral mucosal diseases: Erythema multiforme.
  Br J Oral Maxillofac Surg.
  2008;46:90–95.
  
• Sokumbi O, Wetter DA. Clinical features, diagnosis, and treatment of erythema multiforme: A review for the practicing dermatologist.
  Int J Dermatol.
  2012;51:889–902.
  
• Wetter DA. Pathogenesis, clinical features, and diagnosis of erythema multiforme. In: Callen J, ed.
  UpToDate
  . Waltham, MA: UpToDate; 2013.
  
• Wetter DA. Treatment of erythema multiforme. In: Callen J, ed.
  UpToDate
  . Waltham, MA: UpToDate; 2013.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Herpes
  
• Stevens–Johnson Syndrome
  
• Toxic Epidermal Necrolysis
  

CODES

• 695.10 Erythema multiforme, unspecified
  
• 695.13 Stevens-Johnson syndrome
  
• 695.15 Toxic epidermal necrolysis
  

BASICS

• Erythema nodosum (EN) is characterized by multiple symmetric, nonulcerative tender nodules on the extensor surface of the lowerextremities, typically in young adults.
  
• Peak incidence in 3rd decade
  
• More common in women (4:1)
  
• Nodules are round with poorly demarcated edges and vary in size from 1 to 10 cm.
  
• Skin lesions are initially red, become progressively ecchymotic appearing as they resolve over 3–6 wk.
  
• Lesions are caused by inflammation of the septa between SC fat nodules (septal panniculitis).
  
• Spontaneous regression of lesions within 3–6 wk
  
• Major disease variants include:
  
  • EN migrans (usually mild unilateral disease with little or no systemic symptoms)
    
  • Chronic EN (lesions spread via extension, and associated systemic symptoms tend to be milder)
    

• Immune-mediated response
  
• 30–50% of the time etiology is idiopathic
  
• Often a marker for underlying disease; specific etiologies include:
  
  • Drug reactions:
    
    • Oral contraceptives
      
    • Sulfonamides
      
    • Penicillins
      
  • Infections including:
    
    • Streptococcal pharyngitis
      
    • Mycobacterium tuberculosis
      (TB)
      
    • Atypical mycobacteria
      
    • Coccidioidomycosis
      
    • Hepatitis
      
    • Syphilis
      
    • Chlamydia
      
    • Rickettsia
      
    • Salmonella
      
    • Campylobacter
      
    • Yersinia
      
    • Parasites
      
    • Leprosy
      
  • Systemic diseases:
    
    • Sarcoidosis
      
    • Inflammatory bowel disease
      
    • Behcçet disease
      
    • Connective tissue disorders
      
  • Malignancies such as lymphoma and leukemia
    
  • Catscratch disease
    
  • HIV infection
    
  • Rarely can be caused by vaccines for hepatitis and TB (BCG)
    

Typically, EN begins 2–3 wk after onset of
S. pharyngitis
.

DIAGNOSIS

• Tender erythematous nodules symmetrically distributed on extensor surface of lower legs
  
• Lesions occasionally occur on fingers, hands, arms, calves, and thighs.
  
• In bedridden patients, dependent areas may be involved.
  
• Fever, malaise, leukocytosis, arthralgias, arthritis, and unilateral or bilateral hilar adenopathy with any form of the disease
  

• General symptoms may precede or accompany the rash:
  
  • Fever
    
  • General malaise
    
  • Polyarthralgias
    
• GI symptoms with EN may be a marker for:
  
  • Inflammatory bowel disease
    
  • Bacterial gastroenteritis
    
  • Pancreatitis
    
  • Behcçet disease
    
  • A history of travel is important, as there are regional variations in etiology.
    

• A careful exam is important, as underlying etiology varies by region.
  
• Lesions are most common on the pretibial area but may occur on the thigh, upper extremities, neck and, rarely, the face.
  
• Absence of lesions on the lower extremities is atypical, as are ulcerated lesions.
  
• Lower-extremity edema may occur.
  
• Adenopathy should be evaluated.