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(pĕ-dik′yŭ-lăr) [L. pediculus, a louse] Pert. to or infested with lice.


(pē-dik′yŭ-lāt″) [L. pediculus, a little foot] Pedunculate.


(pē-dik″yū-lō′sĭs) [Pediculus + -osis] Infestation with lice. SEE: Pediculus.

p. capitis A scalp infection caused by head lice, Pediculus humanus capitis, a common parasite in children. Outbreaks are common in schools, esp. among children between the ages of 3 and 11.

 INCIDENCE: Infestation of head lice is common among children between the ages of 3 and 11. Worldwide, millions of cases of head lice occur each year.

 CAUSES: The infection is transmitted principally through direct contact (head-to-head) between children. The common use of personal items such as hair ornaments, combs, hairbrushes, hats, scarves, or coats may also serve as fomite vectors.

 SYMPTOMS AND SIGNS: An itchy scalp is the most common manifestation of head lice infection. The itch results from the frequent feeding of the louse on its human host and injection of louse saliva via its mouthparts. Itching is esp. common around the ears, the nape of the neck, and in the occipital region of the head. Long-standing infestations may produce chronic inflammation and eczema. Secondary bacterial infections of the scalp (impetigo or pyoderma) may occur, and the patient's hair may become matted and malodorous.

 DIAGNOSIS: The adult louse is rarely seen without meticulous observation. Diagnosis is usually made through the identification of eggs (nits), which appear as whitish sac attached to hair.

 TREATMENT: Therapies for lice infestations are modified frequently, to match the resistance of lice to current therapies and to minimize the toxicities of medications. Manual removal of lice always is appropriate and is strongly recommended by lice specialists. Medical treatments include topical or oral ivermectin, pyrethrins or permethrin, lindane and malathion, benzyl alcohol or spinosad. Others recommend the use of insecticides (pediculocides).

 IMPACT ON HEALTH: Rarely, louse infestation is a source of more serious bacterial infections, e.g., infection with Bartonella species carried by the louse vector to humans.

PATIENT CARE: The patient and family are taught how to apply medication to dry hair for lice and are advised that the eyes should be immediately flushed with copious amounts of water if the medication accidentally contacts them. They are informed about minimizing the spread of infection by washing or dry cleaning all clothing and linen used in the home, delousing of rugs and upholstered furniture with sprays or vacuuming, keeping combs and brushes separate, and using medicinal shampoos if there has been contact with the patient. Laundering clothes and bedding at temperatures above 122°F (50°C) kills lice, their nits, and nymphs.


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