P. pubis is a greyish, slate-blue or reddish-brown
louse with crab-like appendages with which
it clings to hairs.Crab lice are small, light brown, flat insects that cling to the pubic hairs, suck blood for nourishment, and fix their eggs (nits) to the pubic hairs. The blood sucking may cause little red sores and itching. Crab lice are almost always spread by close physical contact. They prefer the pubic hair and do not voluntarily leave the body.
The disease is transmitted mainly by close body contact (including sexual activity).
Pubic pediculosis is due to infestation with the crab louse, Phthirus pubis.
P. pubis is a greyish, slate-blue or reddish-brown
louse with crab-like appendages with which
it clings to hairs.
Lice which become detached from the body can live for many hours so that recently contaminated toilet seats, towels, underclothing or bedding can be sources of infestation.
The lice feed on blood several times a day. The female lays eggs which are firmly attached to the hairs close to the skin. The eggs hatch in 7 to 9 days.
The infestation is generally transferred by sexual or close body contact or by using unwashed bedding or clothes worn after their contamination by an infested person. Symptoms and signs can be expected after a variable period which may be several weeks.
Intense irritation is usually the first symptom
after which comes scratching, secondary infection
and eczematous changes.
Pubic lice are rounder than head and body lice and are visible to the naked eye, being 1-2 mm in diameter. They occur less commonly, on hairs from the chest and axillae (armpits) to the knees. They are rarely found on the eyebrows, eyelashes or in the beard.
A history of itching, skin changes, and the demonstration of a louse or nits assists the diagnosis and makes possible the differentiation from "neuro-dermatitis"¡ªa common error.
Observation of pubic lice or nits attached to the hair. The diagnosis is suggested by a history of itching and exposure to lice or observation of crabs by the patient. Pubic lice can also involve eyelashes, eyebrows, beard and body hair. These areas should be examined.
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| The female crab louse - responsible for pediculosis pubis. This louse is just visible with the naked eye - crawling among the pubic hairs. Small eggs (nits) may be seen attached to the pubic hairs. The most common symptom is itchiness in the public region. |
Pediculosis pubis. |
permethrin 1% creme rinse
Permethrin should be applied to clean and cool skin. The patient should not take a hot bath or shower prior to treatment.
Apply to infected and adjacent hairy areas (application from chest to knees is usually recommended). The treatment should be washed off after 20 minutes.
Nits should be removed with a fine toothed comb.
Repeat the treatment in 7 to 10 days.
Sex partners should be treated concurrently.
Clothing and bed linen contaminated by the patient within the past 2 days should be washed and dried by machine (hot cycle) or dry cleaned.
If the eyelashes are infested, white soft paraffin (Lacri-Lube) can be applied to the lashes, and then the eggs removed, twice a day. This treatment should be continued for 7 to 10 days.
Nil. Patient should attend for results of any investigations performed.