Erythrasma is a superficial bacterial infection of the skin folds caused by Corynebacterium minutissimum. It is often misdiagnosed as a fungal infection.


  • C. minutissimum is a part of normal skin flora, but under moist, occluded conditions, the diphtheroid bacteria will cause well-defined, reddish brown plaques in intertriginous areas such as the inguinal, intergluteal, interdigital, and inframammary folds.
  • Concomitant fungal infections, predominately Candida, are seen in ~30% of patients.
  • In the immunocompetent patient, erythrasma may be a minor chronic skin disorder; however, in the immunocompromised population, especially HIV patients, C. minutissimum can progress to severe cellulitis, abscess, or bacteremia (1).


Incidence is reported ~4%. Higher incidence in immunocompromised, predisposed, and elderly populations but has been reported in all ages. Both sexes appear equally affected (2).

Erythrasma appears more in subtropical and tropical areas.

Etiology and Pathophysiology

C. minutissimum is a normal skin bacteria; however, under warm, humid, occlusive conditions, this bacteria invades the stratum corneum layer of epidermis causing it to thicken and scale. These diphtheroids produce porphyrin, which causes bright coral-red fluorescence of the skin under Wood light.

Risk Factors

  • Obesity
  • Diabetes
  • Occlusive clothing/shoes
  • Hyperhidrosis
  • Immunocompromised state
  • Advanced age
  • Living in a subtropical or tropical region

General Prevention

  • Nonocclusive clothing and footwear
  • Good hygiene
  • Weight loss
  • Good blood sugar control
  • Avoiding constant skin friction

Commonly Associated Conditions

Coexisting fungal infections

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