Erythrasma

Erythrasma is a skin infection caused by Corynebacterium minutissimum, a part of the normal skin flora. Optimal conditions for bacterial growth are provided by moist skin fold areas. The infection is particularly common in obese individuals with diabetes mellitus. Patients present with well-demarcated erythematous or brown patches with fine scaling and wrinkling in intertriginous areas (e.g., groin, toe webs). The diagnosis is confirmed by coral-red fluorescence under wood lamp examination. Local disease is treated with topical antibiotic therapy, while extensive disease requires systemic antibiotic treatment.

• Pathogen: Corynebacterium minutissimum
  • Normal skin commensal
  • Gram-positive, aerobic rods
• Risk factors
  • Moist skin fold areas: Obesity, hyperhidrosis, poor hygiene, and hot, humid climates are contributing factors.
  • Immunodeficiency
  • Diabetes mellitus
  • Advanced age

References:^[1][2][3]

• Location: intertriginous areas (e.g., toe webs, groin, axilla)
• Skin lesion: well-demarcated erythematous or brown patches with fine scaling and wrinkling
• Pruritus is usually absent or mild.

References:^[2]

• Wood lamp examination: coral-red fluorescence
• Gram stain of skin scrapings: gram-positive rods

References:^[2][3]

Intertrigo (intertriginous dermatitis) ^[4]

• Definition: dermatitis that particularly affects skin folds (submammary, inguinal, interdigital)
• Etiology
  • Increased moisture in the skin folds (e.g., aggravated by heat, moisture, feces, urine, vaginal discharge)
  • Obesity
  • Immunodeficiency
  • Friction
  • Lack of air circulation
  • Secondary infection: Intertrigo is often colonized by fungal, viral, or bacterial pathogens, most commonly Candida albicans.
• Clinical features
  • Erythematous papules/plaques → macerations, crusting, erosion, or fissures on an erythematous base
  • In addition, if infected with Candida: satellite lesions
• Diagnosis: Secondary infections can be confirmed with microbiological testing.
• Treatment
  • Uncomplicated intertrigo
    • Topical protective and drying agents (e.g., zinc oxide ointment, petrolatum petroleum jelly , talcum powder, aluminum sulfate)
    • Maintaining dry skin and reducing intertriginous friction (e.g., with cotton or linen cloth)
  • If secondary infection is present: Treatment depends on the organism.
    • Candida: e.g., miconazole, clotrimazole, fluconazole
    • Erythrasma: See “Treatment” below.
    • Group A Streptococcus: e.g., mupirocin, erythromycin
• Prognosis: excellent in absence of complicating factors (e.g., immunosuppression/immunodeficiency)

The differential diagnoses listed here are not exhaustive.

• General: improved skin hygiene, maintaining dry skin (e.g., with cotton or linen cloth)
• Medical therapy
  • Localized disease: topical antibiotic treatment (e.g., clindamycin, erythromycin)
  • Extensive disease: systemic antibiotic treatment (e.g., erythromycin)
• Prognosis: Recurrence is common.

References:^[1][2][3]