bubble_chart Overview

Pediculosis is a cutaneous pruritic skin disease caused by lice bites on the human body. The host of human lice is humans; they cannot survive on other animals and can only be transmitted through direct contact between people or indirect contact via clothing, bedding, etc.

bubble_chart Etiology

Disease cause: Lice use their proboscis to pierce the skin and suck blood, excreting feces while feeding. The mechanical irritation from blood-sucking and the release of toxins in their saliva during feeding cause cutaneous pruritus and rashes. Lice are oval-shaped and gray, turning red after feeding. They avoid strong light, prefer darkness, and are active both day and night, remaining motionless when temperatures are too high or too low. Based on their habits, body shape, and the location of infestation, they are classified into three types: head lice, body lice, and pubic lice.

bubble_chart Clinical Manifestations

The female head louse measures 2.7–3.0 mm in length, while the male measures 1.5–2.0 mm. Head lice Chinese Taxillus Herb on the scalp, particularly at the back of the head and behind the ears near the hairline, and are more common in women and children with poor hygiene. Bitten areas may develop erythema and papules, causing intense scalp itching. Frequent scratching can lead to blood crusts, exudation, or secondary infections, causing hair to clump together and emit a foul odor.
Body lice are slightly larger, with females measuring 2.7–4.4 mm and males 2.7–3.6 mm, and are pale gray. They often hide in the seams of clothing and bedding, frequently biting the skin in areas such as the armpits, back, waist, and inner thighs. This can result in erythema, papules, and wheals, causing cutaneous pruritus. Linear scratch marks are commonly seen on the skin, and prolonged scratching may lead to lichenification.

Pubic lice are smaller, with females measuring 1.5–2.0 mm and males 0.8–1.2 mm. They primarily Chinese Taxillus Herb on pubic hair and perianal body hair, though a few may Chinese Taxillus Herb on armpit or chest hair. They are transmitted through sexual contact, often affecting both partners. Pubic lice have a limited range of movement, typically clinging flat to the skin and gripping hair shafts tightly, with their heads burrowed into hair follicles, making them difficult to detect. Their bites cause cutaneous pruritus and papules, and scratching may lead to blood crusts or secondary eczema and folliculitis. Occasionally, bluish or grayish spots about 0.5 cm in diameter may appear near the affected area, likely due to the injection of louse secretions into the skin during biting.

Diagnosis: Based on clinical features, the presence of lice and nits in the affected area confirms the diagnosis.

bubble_chart Prognosis

Prevention and Treatment: Regular bathing, changing clothes, and haircuts are effective methods for preventing and treating pediculosis. Those with body lice should boil their clothes, while individuals with head lice or pubic lice should shave off their hair. For female patients who cannot easily cut or shave their hair, applying 50% stemona root tincture, eurax cream, scabene, or 25% benzyl benzoate emulsion twice daily is recommended. On the third day, wash the hair with hot water and soap, then use a fine-toothed comb to remove lice and nits. For skin lesions, apply calamine lotion, and for infections, use 0.5% neomycin ointment externally.