Caused by the mite Sarcoptes scabiei
Initial lesion is a small, erythematous papule that is easy to overlook. Can have burrows which are pathognomonic.
Most commonly located in interdigital webs, wrist folds, elbows, axilla, genitals, buttocks, and belt line. Face and scalp are usually spared.
In young infants, the palms and soles are also commonly involved. Burrows are most dramatic in patients who are unable to scratch .
Disseminated eczematous eruption results in generalized severe pruritus, especially at night. Can become nodular, particularly in intertriginous areas, or be susceptible to superinfection due to frequent excoriations.
Immunosuppressed patients may develop diffuse scaly crusted eruption and lack pruritus.
5% permethrine cream applied to skin from neck down including under fingernails and toenails. Can repeat in 7 to 10 days.
Launder clothing and sheets. Bag and seal stuffed animals and pillows for 2 to 3 days. Consider treatment of close contacts.