Rosen & Barkin's 5-Minute Emergency Medicine Consult (715 page)

See Also (Topic, Algorithm, Electronic Media Element)

• Lyme Disease
  
• Rocky Mountain Spotted Fever
  

CODES

• 066.1 Tick-borne fever
  
• 088.81 Lyme Disease
  
• 989.5 Toxic effect of venom
  

BASICS

• Superficial fungal infections of the hair, skin, or nails:
  
  • Usually confined to the stratum corneum layer
    
  • Among the most common diseases worldwide
    
• Requires keratin for growth, so does not involve mucosa
  
• Named for location of infection
  

• Dermatophytes:
  
  • Microsporum
    
  • Trichophyton
    
  • Epidermophyton
    
  • Malassezia furfur
    , a yeast, is the etiologic agent of tinea versicolor (not a true tinea)
    
• Trauma or maceration of the skin may allow fungal entry into skin
  
• Transmission may be person to person, animal to person, or soil to person
  

• Fungi can be spread from toys and brushes
  
• Tinea unguium is rare in children and is associated with:
  
  • Down syndrome
    
  • Immunosuppression
    
  • Tinea pedis or capitis
    

DIAGNOSIS

• Tinea capitis:
  
  • Children are predominately affected
    
  • Most contagious dermatophytosis
    
  • Alopecia, dandruff-like scaling
    
  • Kerion:
    
    • Boggy, inflammatory mass that exudes pus and causes cervical lymphadenopathy
      
  • “Black dots” from infected hairs broken off at the scalp
    
• Tinea corporis (“ringworm”):
  
  • Arms, legs, and trunk
    
  • Sharply marginated, annular lesion with raised margins and central clearing
    
  • Hair follicle involvement may produce indurated papules and pustules
    
  • Lesions may be single, multiple, or concentric
    
  • Pets are often a vector
    
• Tinea cruris (“jock itch”):
  
  • Erythematous, scaly, marginated patches involving the perineum, thighs, and buttocks
    
  • Associated with heat, humidity, and tight-fitting undergarments
    
  • Unlike the case in candidiasis, the scrotum and penis are spared
    
• Tinea pedis (“athlete’s foot”):
  
  • Scaling, maceration, fissuring between the toes
    
  • Risk factors:
    
    • Advanced age
      
    • Immunocompromised status
      
    • Hot, humid climates
      
    • Infrequent changing of socks
      
  • More common in adults than children
    
  • Most common tinea infection in US
    
  • “Trichophytid” reaction:
    
    • Vesicular eruption remote from infection
      
    • Involving hands, mimics dyshidrotic eczema
      
• Tinea unguium:
  
  • 1 type of onychomycosis
    
  • Yellow or brown discoloration with thickening and debris under the nails
    
  • Onycholysis: Loosening of the nail from bed
    
  • May involve the plantar surface of the foot
    
• Tinea versicolor (not true tinea):
  
  • Most common in warm months
    
  • Round or oval superficial brown, yellow, or hypopigmented macules that may coalesce
    
  • Upper trunk, arms, and neck
    
  • Facial involvement is common in children
    

• Time of onset from inoculation to visible skin changes is about 2 wk
  
• Main symptom is itching:
  
  • Hair loss with tinea capitis
    
• Participation in contact sports or contacts with similar skin disease
  

• Tinea capitis: Alopecia, broken hairs at scalp surface
  
• Tinea corporis: Areas of exposed skin typically involved with annular scaly plaques, raised edges, may have pustules and vesicles
  
• Tinea cruris: Erythematous lesions on groin and pubic region with central clearing and raised edges
  
• Tinea pedis: Scaling, maceration, and fissuring of toe webs, often only 1 foot affected
  
• Tinea unguium: Separation of nail plate from nail bed with thickened, discolored, broken nails
  

• Diagnose by clinical exam
  
• If diagnosis is in doubt, confirm with microscopy before starting oral antifungals because of possible side effects
  

Fungal cultures are slow growing and should not be routinely done

Generally not indicated

• Wood lamp is insensitive:
  
  • Trichophyton
    , the most common cause of tinea infections, does NOT fluoresce
    
  • Microsporum
    fluoresces bright green
    
  • Malassezia
    (tinea versicolor) fluoresces yellow to yellow-green
    
  • Erythrasma (nontinea corynebacterial infection) will fluoresce coral red
    
• Microscopy:
  
  • Cleanse area with 70% ethanol
    
  • Scrape active margin of lesion with no. 10 or no. 15 scalpel blades
    
  • Place scrapings on a glass slide, add a drop of 10–20% potassium hydroxide solution, and cover with a coverslip
    
  • The presence of septate hyphae confirms dermatophyte infection
    
  • Budding yeasts and short hyphae (“spaghetti and meatballs”) confirms
    Malassezia
    

• Methods to obtain fungal elements for culture or microscopy:
  
  • Brushing the hair with a toothbrush
    
  • Rolling a moistened cotton swab
    
  • Collecting skin cells with transparent tape
    

• Tinea capitis: Impetigo, pediculosis, alopecia areata, seborrheic dermatitis, atopic dermatitis, and psoriasis
  
• Tinea corporis: Impetigo, herpes simplex, Lyme disease, verruca vulgaris, psoriasis, nummular eczema, granuloma annulare, herald patch of pityriasis rosea, erythema multiforme, urticaria, seborrheic dermatitis, and secondary syphilis
  
• Tinea cruris: Impetigo, seborrheic dermatitis, psoriasis, candidal infection, irritant and allergic contact dermatitis, and erythrasma
  
• Tinea pedis: Scabies, erythrasma,
  Candida
  , allergic and contact dermatitis, and psoriasis
  
• Tinea unguium: Psoriasis, dermatitis, lichen planus, and congenital nail dystrophy
  
• Tinea versicolor: Vitiligo, secondary syphilis
  

TREATMENT

Maintain universal precautions.

Only in immunocompromised or septic patients

• Improvement usually occurs within 1–2 wk of treatment; hair and nail tinea require longer treatment of 3–6 mo
  
• Topical antifungals do not penetrate hair/nails:
  
  • Use in conjunction with systemic agent for tinea capitis or unguium.
    
• Tinea capitis:
  
  • Terbinafine is now considered the drug of choice by most:
    
    • Pill form may be crushed in food
      
  • Newer oral antifungals, including terbinafine, itraconazole, and fluconazole, are preferred:
    
    • Retained in tissues longer
      
    • Allows for shorter treatment courses without a decrease in efficacy
      
    • Improved compliance
      
  • Selenium sulfide or ketoconazole shampoo reduces transmissibility
    
  • Kerion may respond more rapidly with addition of prednisone (peds: 1 mg/kg PO QD for 2 wk)