What treatment is recommended for a patient with a disseminated rash on the hands, back, and scrotum?

Treatment of Disseminated Rash on Hands, Back, and Scrotum

Immediate Clinical Priority: Rule Out Disseminated Fungal Infection

The most critical first step is to obtain skin biopsies and fungal cultures from the affected areas to distinguish between disseminated fungal infections (blastomycosis, fusariosis, or mucormycosis) and other causes, as these life-threatening infections require immediate systemic antifungal therapy and carry mortality rates of 50-75% if untreated. 1, 2, 3

Diagnostic Approach

Key Clinical Features to Assess

• Distribution pattern: Disseminated skin lesions on extremities (hands) and trunk (back) with genital involvement (scrotum) suggests hematogenous spread of infection, particularly in immunocompromised patients 1, 2
• Lesion morphology: Determine if lesions are papulopustular, vesicular, necrotic, or urticarial 4, 5
• Immune status: Assess for immunosuppression (chemotherapy, transplant, HIV, hematologic malignancy) as this dramatically changes the differential diagnosis 1, 2, 3
• Fever and systemic symptoms: Persistent fever despite broad-spectrum antibiotics suggests disseminated fungal infection 2, 3

Essential Diagnostic Tests

• Skin biopsy with histopathology and fungal culture from multiple sites is mandatory before initiating empiric therapy 1, 2
• Blood cultures if fever or signs of sepsis are present 1
• Complete blood count to assess for eosinophilia (suggests drug reaction) or neutropenia (increases fungal infection risk) 1, 6

Treatment Algorithm Based on Clinical Presentation

If Disseminated Blastomycosis is Suspected (Endemic Area Exposure)

For moderately severe to severe disease: Start lipid formulation amphotericin B 3-5 mg/kg/day IV for 1-2 weeks until clinical improvement, then transition to oral itraconazole 200 mg three times daily for 3 days, followed by 200 mg twice daily for at least 12 months total. 1

• For mild to moderate disease without systemic symptoms: Oral itraconazole 200 mg three times daily for 3 days, then once or twice daily for 6-12 months 1
• Critical monitoring: Check serum itraconazole levels after 2 weeks to ensure adequate drug exposure 1
• Secondary cutaneous lesions reflect disseminated infection and require systemic therapy, not just topical treatment 1

If Disseminated Fusariosis is Suspected (Immunocompromised Patient)

Voriconazole is the preferred agent, with consideration for combination therapy with terbinafine in severe cases, as amphotericin B alone has limited efficacy. 2, 7

• Fusarium infections present with persistent fever and skin lesions on extremities in 60-80% of cases 2
• Mortality remains 50-75% despite treatment, requiring aggressive management 2
• Combination voriconazole plus terbinafine has shown success in case reports 7

If Drug-Induced Rash (DRESS Syndrome) is Suspected

Immediately discontinue all potentially causative medications, particularly anticonvulsants, sulfonamides, or recently started antibiotics, as DRESS syndrome carries 8% mortality especially with liver involvement. 6

• Check liver enzymes and eosinophil count urgently 6
• If eosinophilia and transaminitis are present with multisystem involvement, start systemic corticosteroids (prednisone 0.5-1 mg/kg/day) 4, 6
• Skin biopsy confirms diagnosis but should not delay treatment if clinical suspicion is high 6

If Simple Dermatitis or Non-Life-Threatening Rash

For widespread urticarial or inflammatory rash without systemic symptoms: Oral prednisone 0.5-1 mg/kg/day plus oral non-sedating antihistamines, combined with topical medium-to-high potency corticosteroids for body areas and lower-potency corticosteroids for genital areas. 4, 8

• Topical hydrocortisone can be applied to affected areas 3-4 times daily for symptomatic relief 8
• For genital area specifically: Use lower-potency topical corticosteroids to avoid skin atrophy 4
• Add emollients and moisturizers twice daily 4

Critical Pitfalls to Avoid

• Never assume a benign cause without biopsy in immunocompromised patients - disseminated fungal infections are rapidly fatal if untreated 1, 2, 3
• Do not use topical therapy alone for disseminated cutaneous lesions - these represent systemic infection requiring systemic antifungals 1
• Avoid corticosteroids if fungal infection is suspected until cultures are obtained, as steroids worsen fungal infections 1
• Do not use fluconazole as first-line for blastomycosis - it is less effective than itraconazole 1
• Recognize that negative cultures do not exclude fungal infection - histopathology from biopsy is essential 3

When to Escalate Care

• Dermatology consultation within 2 weeks if no improvement with initial therapy 4
• Infectious disease consultation immediately if disseminated fungal infection is suspected 1
• Wound specialist for severe desquamation or necrotic lesions 1