Erythrasma

Who gets erythrasma?

• Affects both males and females
• More common in the groin of males
• More common between the toes of females
• More prevalent in:
  • Warm climates
  • Excessive sweating
  • Skin of colour
  • Diabetes
  • Obesity
  • Poor hygiene
  • Advanced age
  • Other immunocompromised states

Cause

• Caused by Corynebacterium minutissimum (gram-positive, non-spore-forming, aerobic or facultative bacilli)
• Can coexist with or be confused with fungal infections (e.g., tinea, Candida albicans)

Clinical features

• Well-defined pink or brown patches with fine scaling and superficial fissures
• Mild itching may be present
• Common sites: armpits, groin, between the toes
• Other sites: intergluteal fold, submammary, periumbilical skin
• Widespread infections often associated with diabetes mellitus

Types of erythrasma

1. Interdigital erythrasma: between the 3rd, 4th, and 5th toe web spaces
2. Intertriginous erythrasma: in armpits, groin, under breasts, and umbilicus
3. Generalised/disciform erythrasma: on the trunk

Complications

• Usually self-limiting
• Can be complicated by:
  • Contact dermatitis
  • Lichenification
  • Postinflammatory pigmentation
  • Coinfection with other bacteria, yeasts, and dermatophytes
• Rare serious complications:
  • Abscess
  • Cellulitis
  • Cutaneous granuloma
  • Endocarditis
  • Pyelonephritis
  • Endophthalmitis
  • Arteriovenous fistula infection
  • Meningitis

Diagnosis

• Typical clinical appearance
• Investigations:
  • Wood lamp skin examination: fluoresces coral-pink due to coproporphyrin III
  • Swab or skin scrapings: microscopy with periodic acid–Schiff, methenamine silver, or Gram stain, or methylene blue

Treatment

• Topical treatments:
  • antiseptic :
    • Benzoyl peroxide or
    • Fusidate sodium 2% ointment topically, twice daily for 14 days
  • topical antibiotic
    • Clindamycin solution
  • Whitfield ointment (3% salicylic acid, 6% benzoic acid in petrolatum)
• Oral antibiotics:
  • Erythromycin – clarithromycin 1 g (adult) orally, as a single dose
  • Tetracycline
• Photodynamic therapy: using red light (broadband, peaking at 635 nm)

Prevention

• Recurrence is common
• Antibacterial soap to prevent recurrence
• Repeat treatment if necessary
• Loose-fitting clothing and antibacterial wash may prevent recurrence
• Antibacterial soap can be used to prevent recurrence.