What is a subcutaneous mite in humans? - briefly
A subcutaneous mite is the larval form of a parasitic arthropod that penetrates human dermal tissue, creating nodular lesions or cysts. The resulting condition, often referred to as cutaneous larva migrans, produces localized inflammation and itching.
What is a subcutaneous mite in humans? - in detail
A subcutaneous mite is an arthropod that inhabits the tissue beneath the epidermis of humans. The most frequently encountered species is Sarcoptes scabiei var. hominis, the causative agent of scabies. Adult females tunnel within the stratum corneum, laying eggs that hatch into larvae, which mature on the skin surface. The burrowing activity creates characteristic linear or serpiginous lesions, accompanied by intense pruritus that intensifies at night.
Other mites may reside in deeper cutaneous structures. Demodex folliculorum and Demodex brevis occupy hair follicles and sebaceous glands; although they primarily remain superficial, heavy infestations can provoke inflammation extending into the dermis. Rare reports describe Sarcoptes variants that penetrate beyond the epidermis, producing nodular granulomas in the subdermal layer.
Epidemiologically, scabies affects all age groups worldwide, with higher prevalence in crowded or impoverished settings. Transmission occurs through prolonged skin‑to‑skin contact or sharing contaminated clothing and bedding. The life cycle from egg to adult spans 10–14 days, allowing rapid population expansion on an infested host.
Clinical assessment relies on visual identification of burrows, dermoscopic examination of mite tracks, or microscopic analysis of skin scrapings. In atypical deep‑tissue presentations, biopsy may reveal mite fragments within granulomatous inflammation.
Therapeutic regimens include topical acaricides such as permethrin 5 % cream applied overnight for a single dose, repeated after one week to eradicate newly hatched mites. Oral ivermectin (200 µg/kg) serves as an alternative for extensive disease or when topical treatment is contraindicated. Adjunctive antihistamines or corticosteroids alleviate pruritus and inflammation.
Preventive measures consist of washing clothing, bedding, and towels at ≥ 60 °C, isolating affected individuals for the duration of treatment, and educating contacts about transmission pathways. Early detection and prompt therapy limit spread and prevent complications such as secondary bacterial infection or post‑streptococcal glomerulonephritis.