53-Year-Old With Spreading Rash

Differential Diagnosis

• Acanthosis nigricans
• Erythrasma
• Inverse psoriasis
• Tinea corporis

Diagnosis

The correct diagnosis in this case is erythrasma. Erythrasma is a common, superficial bacterial infection caused by Corynebacterium minutissimum and may be acute or chronic. It is more common in diabetic patients, immunocompromised patients, obese patients, and older patients. It is also more common in regions with high humidity.

What to Look For

• Distinct, superficial hyperpigmented or erythematous patches localized to intertriginous areas, especially of the axillae, genitocrural crease, and interdigital web space of the toes
• Discoform is a rare variant with round plaques not in the intertriginous areas (as above)
• Lesions are often asymptomatic, although pruritus may be present, especially when it affects the genitocrural region
• Wood’s lamp exam demonstrates coral-red fluorescence

Pearls for Urgent Care Management

• First line treatment is topical antibacterial agents including clindamycin or erythromycin
• The topical imidazole antifungal also has activity against C. minutissimum
• Extensive erythrasma may require oral clindamycin or erythromycin

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Read More

• Identifying And Treating Superficial Fungal Infections In The Urgent Care Setting
• Bariatric Surgery Complications In The Urgent Care Center
• Erythrasma – StatPearls