Scabies
Also called sarcoptes infestation
Mite infestation with an unmistakable epidemiology: nocturnal itch severe enough to wake, itchy household contacts, and burrows in the finger webs, wrists, and genitals.
How it looks
Multiple excoriated papules over the finger webs, volar wrists, and periumbilical skin, with short serpiginous burrows in the web spaces.
Rose is the lesion, grey the pattern the lesions make, green where on the body it lives.
Across skin tones
Papules and burrows may be skin-coloured or hyperpigmented rather than red; nodular scabies on the genitals and post-scabietic pigment change are common in deeply pigmented skin.
Symptoms & course
- Intense itch, worst at night
- Itchy family members or close contacts
- Itch may lag infestation by weeks
Diagnostic approach
- Dermoscopy or scraping of a burrow, the mite, eggs, or scybala confirm
- Clinical treatment threshold is low when epidemiology fits
Differential, and how to separate them
- Atopic dermatitis
Favours it: Flexural pattern, personal atopy, no contacts itching
Against it: New-onset nocturnal itch with itchy contacts is scabies until proven otherwise
Management principles
- Topical permethrin applied neck-down overnight, repeated at one week
- Treat all household contacts simultaneously; launder bedding
- Itch persists for weeks after cure, warn, or the patient re-treats forever
Clinical pearl: The web spaces and wrists are the money sites; the head is spared in adults (not infants).
Keep going
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