Management of endemic outbreaks of scabies with allethrin, permethrin, andivermectin

Background At three residences for the elderly, recurrent scabies infestati ons became out of control. Due to the failure of repeated, nonsynchronized therapeutic eff orts with conventional external anti-scabies treatments, an eradication program had t o be developed. We describe a protocol for the management of outbreaks of s cabies. Methods According to the clinical examination and microscopically identifie d mites, all individuals of the population (IOP: patients, staff, and famil y members) were divided into two groups: (a) healthy and infested IOP; and (b) cases with crusted scabies. The first group was treated simultaneously once with external scabicides (allethrin or permethrin). All others were ho spitalized and treated either with systemic ivermectin or with the latter i n combination with permethrin. Results In 252 IOP living in three residences for the elderly, clinical sig ns of scabies were reported in 91.5%, 78.5%, and 15.4% of the patients (age 55-97 years; mean, 80.5 years), 54.1%, 32.9%, and 16.6% of staff members, and in 7%, 3%, and 0% of family members. The infested IOP showed crusted sc abies (index cases) in 5.3%, 5.0%, and 1.7%, common scabies in 43.1%, 36.7% , and 7.1%, and postscabiotic dermatitis in 10.3%, 7.6%, and 3.5%. In 99.2% of the synchronously treated IOP in group (a) (n = 240), the conventional treatment with permethrin cream 5% or allethrin spray was effective. Group (b) (n = 12) received ivermectin (12 mg) once (n = 5) or twice (n = 7) afte r an interval of 8 days. One index case received permethrin three times. Conclusions Outbreaks of scabies in populations of elderly people require s pecial management for disease control. Synchronous treatment with external permethrin cream 5% or allethrin spray, including all IOP once, and close c ontrol offers a time-saving, cheap, and reliable method. Crusted scabies sh ould be treated by oral administration of ivermectin once or twice after an interval of 8 days. Additional applications of permethrin and mechanical c learing of hyperkeratotic subungual areas shorten the course.