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PekkaAutio

Head Lice and Pubic Lice

Head lice often spread through hats and caps kept in a coat rack. They are also transmitted from person to person in close contact. Pubic lice are most easily transmitted in sexual contact.
If cases of head lice infestation are detected in a day-care centre or a school, the spread of lice should be assessed in the whole community.

Itching and red papules in the scalp and pubic hair.
Secondary pyodermia often develops in the scalp, and the cervical lymph nodes become enlarged.
Pubic lice make red bite marks that cause severe itch in the genital area.
In children pubic lice from the parents may reside in the eyelashes, and there may be vague bluish maculae on the trunk ("maculae coerulae").

Nits (louse eggs) are visible in the hair and pubic hair (picture 1). Nits can remain in hair for months, which is why only nits found less than 6 mm from the scalp are a definite sign of living parasites (hair grows approximately 1 cm in a month). Nits are best found with a louse comb.
Pubic louse nits also typically occur in the hair of the anterior thorax and eyelashes.
Do not mix the "hair cast" phenomenon (a ring of dandruff that glides along the hair) with nits. A nit does not glide but is strongly attached to the hair.
In children the diagnosis of pubic lice can be based on maculae coerulae and nits in the eyelashes.

Application of permethrin shampoo according to the instructions in the package.
If this is not effective, malathion shampoo or solution can be used.
Lotions containing silicone compounds are another alternative. There are several products on the market, and many of them also contain mineral oils or other oil types.
Oral ivermectin is effective against head lice Oral Ivermectin for Head Lice. The dose is 200 µg/kg administered twice at a 7-day interval.
Nits should be combed away with a louse comb (distance between teeth 0.2-0.3 mm) from the very root of the hair. Other combs and brushes are washed with the above-mentioned shampoos.
In daycare centres and schools a communiy health nurse should investigate the head lice situation in the whole community.

For more information: see www http://www.cdc.gov/lice/.

Ivermectin for Parasitic Skin Infections of Lice: A Review of Comparative Clinical Effectiveness, Cost-Effectiveness, and Guidelines [Internet].Young C, Argáez C.Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2019 May 14.
Salavastru CM, Chosidow O, Janier M et al. European guideline for the management of pediculosis pubis. J Eur Acad Dermatol Venereol 2017;31(9):1425-1428. [PubMed]