What does a scabies mite do? - briefly
The scabies mite burrows into the superficial epidermis, feeding on skin cells and fluids, which produces intense itching and a rash. Its tunneling activity provokes an allergic inflammatory response, resulting in characteristic lesions and secondary infections.
What does a scabies mite do? - in detail
The scabies mite (Sarcoptes scabiei) is a microscopic, eight‑legged ectoparasite that lives on the surface of human skin. Adult females measure about 0.3–0.4 mm, enabling them to penetrate the stratum corneum and create tunnels that house the organism and its offspring.
Feeding occurs through the creation of burrows in the epidermis. The mite injects digestive enzymes, then consumes cellular debris and interstitial fluid. This activity provokes a localized inflammatory response, manifesting as intense pruritus that intensifies at night.
The organism’s development proceeds through distinct stages:
- Egg: deposited at the end of a tunnel; hatches in 3–4 days.
- Larva: six-legged form that emerges, migrates to the skin surface, and seeks a new feeding site.
- Nymph: eight-legged stage lasting 2–3 days; undergoes two molts.
- Adult: mature female and male; the female burrows deeper to lay additional eggs, completing the cycle in approximately 10–14 days.
Transmission relies on prolonged skin‑to‑skin contact, typically lasting 10 minutes or more. Indirect spread can occur via contaminated clothing, bedding, or towels, although the mite survives off the host for only 24–36 hours under optimal conditions.
Clinical manifestations include a papular rash, linear burrow tracks, and excoriations resulting from scratching. Secondary bacterial infection may develop when skin integrity is compromised.
Diagnosis is confirmed by microscopic examination of skin scrapings taken from active lesions. Visualization of mites, eggs, or fecal pellets provides definitive evidence.
Therapeutic measures consist of:
- Topical scabicides (e.g., permethrin 5 % cream) applied to the entire body for the recommended duration.
- Oral ivermectin, administered as a single dose of 200 µg/kg, repeated after one week when topical treatment is unsuitable or in severe outbreaks.
- Environmental decontamination: washing clothing and bedding at ≥ 50 °C, drying on high heat, or sealing items in airtight bags for at least 72 hours.
Effective control requires simultaneous treatment of all close contacts and adherence to hygiene protocols to prevent reinfestation.