Clinical features of classic scabies:
(1) generalized itching
(2) nocturnal itching
(3) inflammatory papules or nodules
(4) cutaneous burrows with tiny vesicles at the end
(5) generalized rash with eosinophils if the host becomes sensitized to feces or other antigens
Lesions tend to be found:
(1) interdigital web spaces of the hands
(2) wrist
(3) elbow
(4) axilla
(5) genitalia (males)
(6) breasts (females)
The patient may give a history of pruritic eruption in family members or close contacts.
Complications:
(1) secondary lesions from scratching with subsequent infection - excoriations, impetigo, eczematous eruptions
(2) acute glomerulonephritis if infected with Group A Streptococcus pyogenes
The diagnosis is established by the microscopic identification of mites, feces or eggs in skin scrapings or skin biopsy. A single negative examination does not exclude the diagnosis, especially if performed by a novice or if the rash is sampled rather than a burrow.
