- Clinical science
Scabies is a parasitic skin infestation caused by the Sarcoptes scabiei var. hominis (S. scabiei) mite, which is primarily transmitted via direct human-to-human contact. The female scabies mite burrows into the superficial skin layer, causing severe pruritus, particularly at night. Primary lesions commonly include erythematous papules, vesicles, or burrows. Treatment involves topical medical therapy (e.g., permethrin) and decontamination of all clothing and textiles.
- Pathogen: Sarcoptes scabiei var. hominis
- Highly contagious
- Typically via direct physical contact
- Risk factors: crowded living conditions (e.g., institutions such as nursing homes, child care facilities, and prisons)
- The fertilized, female mite tunnels into the superficial skin layer (stratum corneum), forming burrows in which she lays her eggs and deposits feces (scybala).
- After 2 months, the female parasite dies on site.
- Following a period of 3 weeks, the larvae mature into adult mites, maintaining the infestation cycle.
- The excretions of the mites and their decomposing bodies contain antigens which cause an immunological response (see , presenting as severe pruritus and excoriations.
- Incubation period: approximately 3–6 weeks following infestation.
- Intense pruritus at night
- Burning sensation
- Skin lesions
- Wrists (flexor surface)
- Medial aspect of fingers
- Interdigital folds (hands and feet)
- Male genitalia (e.g., scrotum, penis)
- All other intertriginous areas of the skin (anterior axillary fold, buttocks)
- Periumbilical area or waist
- Additionally in children, elderly persons, and immunosuppressed patients: scalp, face, neck, under the nail, palms of hands, and soles of feet
- Typical history and skin lesions on clinical examination (see “Symptoms/clinical findings” above)
- Environmental diagnosis (direct contact with infected persons)
- Detection of mites, larvae, ova, or mite feces
Medical therapy: topical application of a scabicidal agent
- Drug of choice: permethrin 5% lotion
- Symptomatic treatment of pruritus
- Wash all textiles (e.g., clothing and bedding)
- Bacterial superinfection
We list the most important complications. The selection is not exhaustive.