Why are lice found on eyelashes? - briefly
Lice colonize the lashes because the area around the eye offers warmth, humidity, and access to skin debris that meet their feeding and breeding requirements. This microhabitat allows them to survive and reproduce on the short hairs of the eyelid.
Why are lice found on eyelashes? - in detail
Lice that inhabit the hair surrounding the eyes belong primarily to the species Phthirus pubis (pubic lice) and, less frequently, to Pediculus humanus capitis (head lice). These ectoparasites survive by attaching their claws to coarse hair shafts and feeding on small amounts of blood. The eyelashes provide a suitable environment because their length and density create a protected niche, while the sebum and skin debris near the lid margin supply nutrients.
The infestation process begins when an adult female deposits eggs (nits) on the base of the lash. The eggs hatch in 6–10 days, releasing nymphs that mature within two weeks. Throughout their life cycle, the insects remain on the eyelid margin, moving between lashes to locate blood vessels. Their preference for this region stems from:
- Limited grooming by the wearer, reducing mechanical removal.
- Warm, humid microclimate that favors development.
- Access to thin skin with abundant capillaries.
Transmission occurs through direct contact with contaminated hair or fomites such as towels, pillowcases, or cosmetics. Close interpersonal contact, especially in crowded living conditions, increases the likelihood of spread. Children and individuals with compromised hygiene are particularly vulnerable.
Clinical signs include itching, redness, and a gritty sensation as the lice move. Secondary bacterial infection may arise from scratching. Diagnosis relies on visual identification of live insects or attached nits at the base of the lashes, often aided by magnification.
Effective management involves:
- Topical pediculicides approved for ocular use (e.g., 1 % permethrin lotion, applied with careful shielding of the eye).
- Manual removal of nits using fine tweezers under magnification.
- Cleaning of personal items (bedding, towels) in hot water or disposable disposal.
- Education on avoiding shared cosmetics and personal items.
Follow‑up examination after 7–10 days confirms eradication; persistent symptoms warrant repeat treatment. Prevention focuses on maintaining personal hygiene, avoiding shared grooming tools, and promptly treating any identified infestation elsewhere on the body.