What are subcutaneous lice? - briefly
Subcutaneous lice are parasitic insects that embed beneath the skin of mammals to feed on blood, causing irritation and inflammation. Unlike head or body lice, they inhabit the dermal layer rather than the external surface.
What are subcutaneous lice? - in detail
Subcutaneous lice are ectoparasitic insects that inhabit the space beneath the host’s skin, typically causing localized inflammation and tissue damage. They belong to the order Phthiraptera, family Pediculidae, and differ from common head or body lice by their ability to burrow into the dermal layer rather than remaining on the surface.
The adult female measures 2–3 mm, possesses a flattened body adapted for movement through connective tissue, and lays eggs (nits) within the subdermal cavity. The life cycle comprises egg, three nymphal instars, and adult stages; development from oviposition to mature adult requires 7–10 days under optimal temperature (25–30 °C) and humidity (70–80 %). Nymphs feed on blood, causing erythema, papules, and occasional secondary infection.
Key clinical features include:
- Persistent, pruritic nodules at attachment sites
- Small, raised lesions with central punctum
- Possible ulceration if infestation is heavy
- Regional lymphadenopathy in severe cases
Diagnosis relies on dermoscopic examination or skin biopsy, revealing characteristic mouthparts and embedded nits. Molecular methods, such as PCR targeting mitochondrial COI genes, provide species‑level identification when morphological assessment is inconclusive.
Effective management combines mechanical removal and pharmacologic therapy. Recommended measures are:
- Extraction of visible lice and nits with fine forceps under magnification.
- Topical application of 5 % permethrin or 1 % ivermectin cream, applied for three consecutive days.
- Oral ivermectin (200 µg/kg) in a single dose for extensive infestations.
- Post‑treatment antiseptic dressing to prevent bacterial superinfection.
Prevention emphasizes personal hygiene, regular inspection of high‑risk populations (e.g., institutionalized elderly, individuals with compromised immunity), and environmental control through laundering of clothing and bedding at ≥60 °C. Education of caregivers on early detection reduces transmission and complications.
Epidemiological data indicate higher prevalence in tropical regions, where humidity facilitates larval survival. Reports from temperate zones show sporadic cases linked to travel or close contact with infected individuals. Ongoing research focuses on resistance patterns to topical insecticides and the development of novel antiparasitic agents targeting the lice’s unique cuticular proteins.