pääske

Pääske, in Finnish, refers to the head louse, a small parasitic insect that infests the human scalp and hair. The species most commonly associated with humans is Pediculus humanus capitis. A head louse spends its life on the host, feeding on blood and laying eggs (nits) at the base of hair shafts.

Life cycle and biology: Eggs are laid near the scalp and hatch after about 7–10 days. Nymphs molt three times before reaching adulthood. Adults live for roughly 2–4 weeks, with females capable of producing several eggs per day. Transmission occurs mainly through direct head-to-head contact, but can also happen via shared combs, hats, bedding, or headphones.

Symptoms and diagnosis: The most common symptom is itching due to an allergic reaction to louse saliva. Visible lice or eggs glued to hair near the scalp can confirm infestation. Nits are often found close to the scalp and are firmly attached to hair shafts, making them easy to miss if not closely examined.

Treatment and prevention: Treatments include topical pediculicides containing permethrin or pyrethrins, used according to label instructions, often with a second treatment about 7–10 days later to kill newly hatched lice. Combing with a fine-toothed nit comb helps remove remaining eggs and insects. Laundry of clothes and bedding in hot water, vacuuming, and cleaning of shared spaces reduce spread. Close contacts may require screening and treatment if infested. Preventive measures include not sharing personal items, regular checks, and, in schools, routine screening and notification when cases are found.

Epidemiology and history: Head lice infestations are common worldwide, particularly among school-age children. The condition is not a sign of poor hygiene. In Finnish medical literature, pääske is the term used to describe this infestation.