Differential Diagnosis for Eczema on Feet with Fungal Rash

Single Most Likely Diagnosis

• Dyshidrotic Eczema with Secondary Fungal Infection: This condition is characterized by small, itchy blisters on the feet, which can become secondarily infected with fungi, especially in warm, moist environments. The presence of both eczema and a fungal rash on the feet makes this a highly plausible diagnosis.

Other Likely Diagnoses

• Athlete's Foot (Tinea Pedis) with Eczematous Reaction: Athlete's foot is a common fungal infection of the foot that can cause itching, cracking, and flaking skin. An eczematous reaction to the fungal infection could explain the presence of both conditions.
• Contact Dermatitis with Fungal Superinfection: Contact dermatitis is a type of eczema caused by an allergic reaction or irritation from substances like soaps, detergents, or certain materials. If the affected skin becomes superinfected with a fungus, it could present as a fungal rash on top of eczema.
• Seborrheic Dermatitis with Fungal Infection: Although less common on the feet, seborrheic dermatitis can occur in this area and may become secondarily infected with fungi, presenting with a combination of eczema and fungal rash.

Do Not Miss Diagnoses

• Cellulitis: A bacterial infection of the skin and subcutaneous tissues that can present with redness, swelling, warmth, and sometimes blistering or rash. It's crucial to differentiate cellulitis from eczema and fungal infections due to its potential for serious complications if not treated promptly with antibiotics.
• Erythrasma: A bacterial infection caused by Corynebacteria, which can present similarly to fungal infections and may be found in the interdigital spaces of the feet. It's essential to consider erythrasma to ensure appropriate antimicrobial treatment.

Rare Diagnoses

• Pitted Keratolysis: A bacterial infection of the skin on the feet, characterized by small pits in the skin and often accompanied by a foul odor. While it doesn't typically present with eczema, in rare cases, it could be confused with a fungal infection or coexist with eczematous changes.
• Keratoderma Blennorrhagicum: Associated with reactive arthritis, this condition presents with skin lesions on the feet that can resemble eczema or fungal infections. It's a rare consideration but important in the context of systemic disease.