Clinical Scorecard: Disseminated Crusted Scabies Following Rituximab Therapy in a Patient With Systemic Sclerosis–Lupus Overlap Syndrome

At a Glance

Key Highlights

• A 17-year-old girl with juvenile systemic sclerosis–systemic lupus erythematosus overlap syndrome presented with 4 months of progressive skin scaliness and recurrent finger gangrene; four months earlier, she had taken rituximab, methotrexate, and high-dose prednisolone for 1 month.
• Skin scraping identified Sarcoptes scabiei mites and ova, confirming crusted scabies.
• Treatment included oral ivermectin on days 1, 2, 8, 9, 15, 22, and 29, topical permethrin, and intravenous antibiotics for bacterial finger infection.
• Family members had comparable but less severe symptoms without dissemination and received single-dose ivermectin.
• Marked clinical improvement was documented 5 months after treatment.

Guideline-Based Recommendations

Diagnosis

• The authors state that crusted scabies warrants consideration in immunosuppressed patients with refractory dermatitis, including those without classic burrows.
• In this case, skin scraping showing mites and ova confirmed the diagnosis.

Management

• The reported regimen was oral ivermectin 200 mcg/kg on days 1, 2, 8, 9, 15, 22, and 29, plus topical permethrin 5% daily for 7 days and then twice weekly.
• Permethrin was applied to the entire body from the chin downward, including toes and beneath the fingernails and toenails.
• Intravenous antibiotics were given for bacterial finger infection; family members received single-dose ivermectin.

Monitoring & Follow-up

• The patient had discontinued follow-up and treatment before this presentation and did not attend follow-up after the treatment and immunosuppressive therapy given four months earlier.
• Marked clinical improvement was documented 5 months after scabies treatment.

Risks

• The authors considered rituximab-associated B-cell depletion a likely factor in compromised mite clearance and hyperinfestation.
• The patient had infected digital gangrene requiring intravenous antibiotics.

Patient & Prescribing Data

A 17-year-old girl with juvenile systemic sclerosis–systemic lupus erythematosus overlap syndrome and prior digital ischemia.

Four months before presentation, she received ivermectin for 3 days and took rituximab, methotrexate, and high-dose prednisolone for 1 month. Reported scabies treatment comprised oral ivermectin 200 mcg/kg on days 1, 2, 8, 9, 15, 22, and 29; topical permethrin 5% daily for 7 days and then twice weekly; and intravenous antibiotics for bacterial finger infection. Empirical intravenous immunoglobulin was given at 0.4 g/kg daily for 5 days because serum IgG had not been measured before infusion.

Clinical Best Practices

• Reported diagnostic finding: skin scraping identified mites and ova.
• In this case, topical permethrin was applied to the whole body from the chin downward, including toes and areas beneath the fingernails and toenails.
• The patient received intravenous antibiotics for bacterial finger infection.
• Family members with comparable but less severe symptoms received single-dose ivermectin.

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