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A 28 year old unmarried, sexually active male came to us with generalised body itching of 15 days’ duration. He also complained of itching and irritation of eyelid margins. He had noticed some concretions attached to his eyelashes and some crawling insects over his body. He gave a history of frequent heterosexual unprotected genitogenital contacts with commercial sex workers. The last sexual contact had been about a month previously. On physical examination, both eyes appeared normal except for eyelid margins, which showed brownish scales and louse nits on the upper eyelashes (fig 1). The pubic area and thigh showed live adult crab lice clinging to the hair (fig 2). Under the light microscope, they were found to have short stout bodies and well developed claws in the second and third pair of legs, typical of the crab louse. His serology for the venereal disease research laboratory test and HIV antibodies was non-reactive/negative. He was treated with 1% gamma-benzene hexachloride lotion topically with a single overnight application (below the neck all over the body) and this was repeated after one week. The eyelash infestation was successfully managed with liquid petrolatum ointment topically and manual removal of nits and lice.
Pediculosis, infestation by the Pediculus corporis and Pediculus capitis, and phthiriasis, infestation by the Phthirus pubis (crab louse) occur in humans when sanitary practices are inadequate. Typically, P pubis is found in the hair of pubic and inguinal regions, the P corporis on the seams of clothing, particularly where it is in close, constant contact with the body.
Pediculosis is transmitted by close contact with an infested individual or by contaminated clothing and bedding. Phthiriasis, on the other hand, is typically transmitted by sexual contact. Eyelashes and eyebrows are sites of predilection for phthiriasis in children; the source of infestation is an infested mother. In adults, phthiriasis palpebrarum results from probable transmission of the crab louse from the genital area to the eyes by hand. The infestation of eyelashes is rare and is rarely encountered by dermatologists. The crab louse infests the eyelashes most commonly, but is nevertheless rare. Primarily, it manifests as itching and irritation of eyelid margins. The signs of typical blepharoconjunctivitis, blood stained thickened discharge on the eyelid margins, and the presence of nits on the eyelashes and adult parasites in their roots are distinctive features of this entity. It may be confused with other forms of blepharitis, unless one looks for the above signs. Diagnosis can be confirmed by microscopic examination of the louse. Morphologically, P pubis may be distinguished from pediculus by its much broader abdomen and stronger second and third pair of legs (its distinctive crablike appearance). Other areas of the body may be affected by the adult crab louse, for example, the pubic area, thighs, abdomen, and axillae.
Infestation of the eyelids is treated with twice daily applications of petrolatum for seven to 10 days. Alternative treatments include anticholinesterase eye ointments, yellow oxide of mercury, or fluorescein. The simplest technique for the treatment of eyelid lice is direct removal of the lice and nits with fine forceps. Cryotherapy may provide a fast cure. Application of 1% gamma-benzene hexachloride cream and pyrethrin ointment are other options. As one third of patients with pubic lice infestation may have other sexually transmitted diseases, they should be examined for these infections. Clothing and bed linen must be washed and heat dried after each treatment.