Visual Diagnosis

Case: A 6-year-old girl presents with an itchy rash on her arms, trunk, and legs for the past week. Her mother also developed a similar rash several days ago. They both deny any new travels, detergents, soaps, or exposures. There are no recent fevers or signs of infections. Small papules are found generalized on the child’s body, and mostly on the hands and arms of her mother.

Diagnosis:

This patient has scabies.

Scabies is caused by the mite Sarcoptes scabiei var homini, which burrows under the skin. Patients usually present with pruritic papules or a vesicular rash. Distribution of the rash in children and adults is usually between finger webs, in the axilla, on the waist, underneath the breast, and around genitalia. Infant presentations are more generalized, with a rash on the face, neck, palms, and soles of the feet. Diagnosis is usually clinical or through skin scraping. First-line treatment is permethrin 5% cream, followed by ivermectin if symptoms persist.

Clinical Practice Pearls:

• Consider crusted scabies (Norwegian scabies) in patients with persistent symptoms or in immunosuppressed patients.
• Inform patients that pruritus may persist for 2 weeks after treatment.
• Clothing and sheets in direct contact with individuals with scabies should be laundered in hot water and dried in the dryer, or placed in a plastic bag for at least 72 hours.

Additional Reading:

• Gunning K, Pippitt K, Kiraly B, et al. Pediculosis and scabies: a treatment update. Amer Fam Physician. 2012. 84(6):535-541.