Lice — what disease is it? - briefly
Lice are small, wingless parasitic insects that live on human hair and feed on blood, producing intense itching and possible secondary skin infection. They constitute a contagious infestation rather than a disease and are eliminated with approved topical pediculicides.
Lice — what disease is it? - in detail
Lice are small, wing‑less insects that live on the human scalp, body, or clothing and feed on blood. Three species commonly affect people: head lice (Pediculus humanus capitis), body lice (Pediculus humanus corporis), and pubic lice (Pthirus pubis). Each species has a distinct habitat, morphology, and pattern of spread.
Head lice inhabit the hair shafts near the scalp, laying eggs (nits) firmly attached to strands. Nits hatch in about seven days, releasing nymphs that mature in another week. Infestation causes itching, redness, and sometimes secondary bacterial infection from scratching.
Body lice reside in seams of clothing, moving to the skin only to feed. They emerge when clothing is infested, laying eggs on fabric fibers. Their life cycle mirrors that of head lice, but transmission often occurs in crowded, unhygienic conditions, leading to diseases such as trench fever, relapsing fever, or epidemic typhus.
Pubic lice attach to coarse body hair, including the genital region, chest, and facial hair. They lay eggs close to hair shafts, causing intense itching and inflammation. Transmission is primarily sexual, though indirect spread via contaminated bedding or clothing is possible.
Key aspects of identification and diagnosis:
- Visual inspection of hair or clothing for live insects and attached nits.
- Microscopic examination can confirm species.
- Absence of fleas or other arthropods helps differentiate.
Effective management includes:
- Mechanical removal: combing with a fine-toothed lice comb to extract nits and adults.
- Topical pediculicides: permethrin 1 % lotion, pyrethrin‑based products, or dimethicone, applied according to label instructions.
- Oral agents: ivermectin or malathion for resistant cases, prescribed by a healthcare professional.
- Environmental control: washing bedding, clothing, and personal items at ≥ 60 °C or sealing non‑washable items in plastic bags for two weeks.
Prevention strategies focus on avoiding direct head-to-head contact, not sharing personal items such as combs, hats, or towels, and maintaining regular hygiene. In institutional settings, routine screening and prompt treatment of identified cases reduce outbreak risk.
Complications are generally limited to secondary skin infections, but body lice can transmit serious bacterial pathogens, underscoring the need for comprehensive treatment and environmental sanitation.