bubble_chart Overview

Pediculosis is a skin disease caused by lice and occurs worldwide. Pubic lice are a type of pediculosis that can be transmitted through sexual contact, often affecting couples, with women being more commonly affected. In recent years, it has been prevalent in the United States and Western Europe.

bubble_chart Etiology

Lice can be divided into three types based on their morphology and the parts of the Chinese Taxillus Herb they inhabit: head louse, body louse or clothes louse, and pubic louse. They reside on human hair, underwear, and pubic hair, respectively. All feed on human blood and release toxic saliva during feeding. Both their bites and venom can cause cutaneous pruritus dermatitis. Clothes lice can spread pestilence, relapsing fever, epidemic macula and papule cold-damage disease, and trench fever. Pubic lice generally do not transmit pestilence, but individual reports suggest that under certain circumstances, they may spread pestilence macula and papule cold-damage disease.

Pubic lice are shorter and broader than head and body lice. Female lice measure 1.5×2.0 mm, while males measure 0.8×1.2 mm. They have three pairs of legs, with the front pair being slender and the other two pairs equipped with hook-like claws. Their thorax and abdomen are fused without a clear boundary, and their abdomen is short and wide, resembling a crab. They typically grip pubic and anal hair tightly with their large claws. Spread to armpit hair, eyebrows, or eyelashes is rare.

They usually cling to nearby hair and use their mouthparts to suck blood, but they can also crawl on the skin, appearing as small grayish-yellow particles. They are generally confined to pubic hair or the lower abdomen. Their eggs cling diagonally to pubic hair, appearing as rust-colored or pale red specks, sometimes resembling dotted blood scabs, making them easily distinguishable from the white eggs of head lice.

Pubic lice are photophobic and prefer dark environments, remaining active day and night. They become motionless when temperatures are too high or too low. After mating, adult females are fertilized within 24 hours and begin laying eggs. Pubic lice produce few and small eggs. In the 24-48 hours before death, they lay about 3 eggs per day, totaling around 50 eggs in their lifetime. Adult lice live for about 30 days and die within 24 hours of leaving the host. Lice undergo incomplete metamorphosis, with their life cycle consisting of eggs, nymphs, and adult late stage [third stage], all completed on the host. When laying eggs, female lice secrete a glue-like substance to firmly attach the eggs to hair or fabric fibers.

bubble_chart Diagnosis

Pubic lice inhabit the pubic and perineal hair. They exhibit a certain degree of mobility, causing cutaneous pruritus in the pubic hair area and its vicinity. Scratching may lead to excoriations, blood crusts, or secondary infections such as impetigo and folliculitis. Occasionally, soybean-sized or fingernail-sized Dyers Woad spots—small, grayish pigmented spots generally no larger than 1 cm in diameter—may appear at the bite sites. These spots may be an allergic reaction to the saliva of pubic lice, or some suggest they result from the discoloration of hemoglobin when the lice's saliva enters the bloodstream during feeding, causing minor bleeding and forming bluish spots. These spots may persist for several days even after the lice are eradicated. Pubic lice can be found at the hair follicle openings, and rust-colored nits (eggs) may be observed on the hair shafts.

[Auxiliary Examination]

Specimen Collection: Use scissors to cut pubic hair with lice or nits attached.

Specimen Fixation: Fix the specimen with one of the following solutions: 70% alcohol or 5%-10% formaldehyde solution. Place the fixed specimen on a glass slide, add a drop of 10% potassium hydroxide solution, and gently heat it over an alcohol lamp before microscopic observation.

Results: Pubic lice are crab-shaped with three pairs of legs—the front legs are smaller, while the middle and hind legs are large and equipped with robust claws for gripping pubic hair. The nits appear rust-colored or pale red.

Patients can self-diagnose by identifying lice or nits on Chinese Taxillus Herb. Observe their characteristics under a microscope.

bubble_chart Treatment Measures

Treatment measures:

It is best to shave the pubic hair, boil or iron the underwear, and apply 1% malathion powder externally. Chinese medicinals include 25-50% stemona root tincture, 1% r-666 cream, or 25% benzyl benzoate emulsion, all of which can kill lice. Alternatively, insecticide spray can be used for local application, followed by washing after 3 minutes.