Pediculosis is the parasitic infestation of different forms of lice; head, body and crab or pubic lice. All these forms of lice feed on human blood, and lay their eggs on body hairs and clothing fibers.
Nits hatch to give lice, which has to be fed within 24 hours, lest they die. They mature in 2-3 weeks’ time and on biting the victim, injects a toxin into the skin to trigger mild irritation and a purpuric spot. While repeated bites lead to sensitization to the toxin, it can lead to more serious inflammations.
Causes
Head lice feeds on the scalp and in rare cases in the eyebrows, beard and eyelashes. They are triggered by overcrowded conditions and poor personal hygiene. They commonly affect children, especially girls and spreads through sharing of combs, hairbrushes, hats and clothes.
Body lice lives in seams of clothes but feeds only on blood. Prolonged wearing of the same clothes, poor personal hygiene and overcrowding can trigger body lice, which is spread through shared clothes and bed sheets.
Pubic lice are found mainly in pubic hair, and can extend to the eyebrows, eyelashes or body hair. It is transmitted through sexual intercourse and contact with infested clothes, towels and bed sheets.
Symptoms
Head lice symptoms include itching, foul-smelling and lusterless hair, excoriation and a rash on the trunk with sensitization. Adult lice then migrate to the scalp to leave oval, gray-white nits on hair shafts.
Body lice produce red papules, and if left untreated, can lead to vertical excoriations and consequent dry, discolored and scaly skin. In severe cases, there may also be fever, headache and malaise with cutaneous symptoms.
Pubic hair produces skin irritation from scratching, and sometimes, there may be small, gray-blue spots on the thighs or upper body.
Diagnosis and treatment
Head lice are found as oval and grayish nits that don’t shake loose like dandruff while body lice occur as characteristic skin lesions and are found on clothing. Pubic nits are attached to pubic hairs and feel coarse and grainy to touch.
Head lice are treated by rubbing permethrin cream rinse into hair and rinsing after 10 minutes. Nits can be removed using a fine-tooth comb dipped in vinegar while washing hair with ordinary shampoo removes encrustations.
Body lice are removed by bathing with soap and water while lice on clothes can be removed by washing them in hot water and ironing or dry-cleaning them. Apply 10% lindane powder on clothes that cannot be washed.
Applying a topical pediculocide helps treat pubic lice while other agents like permetrhin cream and lindane ointment are also prescribed by health care providers. Reinfestation is prevented by washing clothes and bed sheets.
The latest treatment option used for clearing the hair of head lice is a single application 0.9% spinosad, which is derived from soil bacteria. At the end of the trial, there were no lice eggs visible after combing as unlike other topical therapies for lice, spinosad kills nits.