How is it Diagnosed?
Scabies is a contagious skin infestation caused by the Sarcoptes scabiei mite. Diagnosis
primarily relies on clinical evaluation. The hallmark symptom is intense itching,
especially
at night, along with a characteristic rash consisting of small papules, burrows, and
vesicles, typically found in web spaces of fingers, wrists, axillae, waistline, and
genital
areas.
A thorough history is essential, focusing on the onset of symptoms, contact with
affected individuals, and living conditions. Family members or close contacts showing
similar symptoms support the diagnosis.
Physical examination may reveal linear burrows—thin, grayish, wavy lines indicating
mite
tunnels. In atypical presentations or in crusted (Norwegian) scabies, diagnosis may be
challenging.
Definitive diagnosis is made by identifying mites, eggs, or fecal pellets under a
microscope. This is done by performing a skin scraping from a suspicious lesion,
applying mineral oil, and examining the sample microscopically.
Dermoscopy can also assist in identifying the “jet with contrail” appearance,
representing the mite and its burrow. In crusted scabies, multiple skin areas may need
to be sampled.
When microscopic confirmation is not possible, empirical treatment is often initiated
based on clinical suspicion, especially in high-risk or outbreak settings like nursing
homes.