What can cause lice in an adult? - briefly
Adult head‑lice infestations arise from direct head‑to‑head contact with an infested person, sharing personal items such as combs, hats, or pillows, and, less commonly, from contact with contaminated clothing or bedding.
What can cause lice in an adult? - in detail
Adult infestations arise primarily from direct head‑to‑head contact, a transmission route that does not require prolonged exposure. Sharing combs, brushes, hats, helmets, or pillowcases can transfer viable nits and adult lice. Environments where many people gather—schools, dormitories, homeless shelters, military barracks, and correctional facilities—facilitate rapid spread because close proximity increases the likelihood of accidental contact.
Additional factors include:
- Contact with an infested child: Adults caring for or co‑habiting with children who have lice are at heightened risk.
- Occupational exposure: Hair‑dressers, barbers, and healthcare workers who handle patients or clients with lice may acquire the parasites through tools or personal protective equipment.
- Compromised scalp conditions: Scalp dermatitis, psoriasis, or excessive sebaceous secretions can create a favorable habitat for lice, though poor hygiene alone does not cause infestation.
- Crowded living conditions: Limited personal space and shared bedding elevate transmission chances.
- Travel to regions with high prevalence: Visiting areas where lice are endemic increases exposure risk, especially when staying in hostels or communal lodging.
Body lice, distinct from head lice, thrive in clothing and bedding rather than on the scalp. Infestation occurs when garments are infrequently washed or when individuals live in unsanitary settings. Pubic lice, transmitted primarily through sexual contact, may also affect adults who engage in close intimate activities.
Effective prevention relies on minimizing direct contact, avoiding the exchange of personal grooming items, and maintaining regular laundering of clothing and bedding at temperatures above 130 °F (54 °C). Prompt identification and treatment of any case in a household or workplace curtail further spread.