Snap Shot A 21-year-old female presents to her primary care physician after recently having unprotected sexual intercourse at a college party "a few weeks ago". She complains of intense genital pruritis that has been going on for the past 3 days. Nothing she has tried has alleviated the intense itching. Introduction Parasitic infection of human pubic hair and skin by lice caused by Pthirus pubis the lice do not transmit disease Epidemiology incidence approximately 2% of the population risk factors poor hygiene unprotected sexual intercourse transmission sexual contact fomites clothing towels Mechanism & Pathophysiology female louse lays eggs (nits) at the base of the hair lice can be visible to the naked eye 3-4 mm in size the lice are obligate parasites that feed on human blood Associated conditions other STDs Presentation History pubic pruritis sexual contact with someone diagnosed with pediculosis pubis Symptoms intense itching of the pubic area due to parasitic saliva becomes stronger over 2 or more weeks after initial infestation other hairy areas of the body can be involved pyoderma may develop from scratching some patients are asymptomatic Evaluation Diagnosis examination of hair under microscope identification of adult lice or nits Treatment General proper cleaning of clothing and bedding is necessary Pharmacologic permethrin 1% shampoo apply to all hairy regions from the neck down sexual partners should be treated as well lindane indications 2nd line treatment due to toxicities side effects contraindicated in pregnancy headaches seizures dizziness convulsions