Wednesday, November 5, 2014

A 22-year-old male comes to the clinic reporting severe penile itching and new skin lesions

A 22-year-old male comes to the clinic reporting severe penile itching and new skin lesions. His last sexualencounter was unprotected sex 3 weeks prior with a new
female partner in her bed. He has not seen her since. Over
the last 3 days he’s noticed new lesions on his penis and
scrotum. The lesions are extremely pruritic, particularly
at night and after a shower. His physical examination is
shown in Figure . Which of the following is the best  therapy?
A. Ceftriaxone plus azithromycin
B. Metronidazole
C. Penicillin G
D. Permethrin
E. Vancomycin


The answer is D. 
Scabies, the human itch mite, remains a common problem due to its high degree of infectivity and ability to cause symptoms. It is a common reason for seeking attention from dermatologists and is thought to affect over 300 million people worldwide. Transfer is facilitated by intimate contact, and outbreaks may occur in nursing homes, mental institutions, and hospitals. The itching and rash associated with scabies derive from a sensitization reaction directed against the excreta that the mite deposits in its burrow. 

An initial infestation remains asymptomatic for up to 6 weeks, and a reinfestation produces a hypersensitivity reaction without delay. Intense itching worsens at night and after a hot shower. Typical burrows may be difficult to find because they are few in number and may be obscured by excoriations. Burrows appear as dark wavy lines in the epidermis and measure up to 15 mm. Lesions occur most frequently on the volar wrists, between the fingers, on the elbows, and on the penis. Small papules and vesicles, often accompanied by eczematous plaques, pustules, or nodules, are distributed symmetrically in those sites and in skinfolds under the breasts and around the navel, axillae, belt line,
buttocks, upper thighs, and scrotum. Except in infants, the face, scalp, neck, palms, and soles are spared. 

Burrows should be sought and unroofed with a sterile needle or scalpel blade, and the scrapings should be examined microscopically for the mite, its eggs, and ts fecal pellets. Permethrin cream is effective therapy. Ivermectin has not been approved y the U.S. Food and Drug Administration (FDA) for use against any form of scabies,but a single oral dose effectively treats scabies in otherwise healthy persons. CeftriaxonePlus azithromycin is recommended treatment for suspected gonorrhea and chlamydiainfection, and metronidazole for trichomonas in women. The lesions shown in Figure
 are not consistent with the single painless chancre of syphilis that is treated with
penicillin G.


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