Penis and scrotum

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Penis and scrotum

Infectious disorders lesions

Scabies

Reviewers: Antonio Cubilla, M.D. and Alcides Chaux, M.D. (see Author/Reviewers page)

Revised: 18 February 2010, last major update February 2010

Definition

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● Most common parasitic infection of penis, usually part of generalized infection

Sites

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● Red papules or nodules on glans, shaft and scrotum are typical

Etiology

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● Caused by infestation with mite Sarcoptes scabiei var hominis, which burrows into the skin and causes intense itching

● Spread by prolonged (15 to 20 minutes) skin-to-skin contact with an infected individual, often as a sexually transmitted disease or between members of a household

● Animals can get scabies, but do not spread human scabies

Clinical features

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● First human disease recognized as caused by a specific pathogen (eMedicine)

● Highly contagious and difficult to diagnose early

● Symptoms may not occur for up to 6 weeks after infection (Clin Microbiol Rev 2007;20:268)

● Diagnosis requires examining the skin for burrows, then confirming the presence of mites, ova or scybala by microscopy (Dermatol Ther 2009;22:279)

● Main symptom is intense pruritus, which is worse at night or after hot baths

● Small crooked lines 4-6 mm long (scabetic burrows) and erythematous papules and nodules are often present on glans, shaft and scrotum

● Excessive scratching may lead to sores, bacterial infections and even glomerulonephritis (Postgrad Med J 2004;80:382)

● Patients with immunocompromise are at risk for developing “crusted scabies”, also called “Norwegian scabies”, characterized by scaly rashes, a thickening of the skin, and an overwhelming number of mites (J Am Podiatr Med Assoc 2004;94:583)

● Clinically, scabies can mimic eczema, mycosis fungoides, syphilis and bullous pemphigoid (Dermatol Online J 2006;12:19)

● Scratch marks often obscure signs of burrows

Case reports

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● 45 year old man with HIV and localized crusted scabies on glans (Sex Transm Infect 2004;80:72)

● 52 year old woman with lesions on leg (Case of the Week #160)

Treatment

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● Topical permethrin (drug of choice), crotamiton (CDC); possibly topical lindane or oral ivermectin (Am J Clin Dermatol 2002;3:9)

● Topical treatments must coat the body to be effective

● Household members and close personal contacts should be treated at the same time

● Nodules may persist for weeks after mites are killed

● Bedding or clothing of infected individuals should be machine washed and dried with hot water or sealed in a plastic bag for at least 3 days (Centers for Disease Control and Prevention)

Clinical images

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Scabies on penis

Localized Norwegian scabies Norwegian scabies in AIDS patient

in AIDS patient

Mite #1 #2 Burrow #1 #2

Micro description (Histopathology)

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● Mite and scybala (hardened masses of feces) in epidermis

● Scabetic burrows are observed in the stratum corneum of the epithelium

Micro images

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Lesion on leg (fig 1 & 2: mites in the epidermis; fig 3: mite and scybala (hardened masses of feces)

Additional references

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● Wikipedia, DermNetNZ, eMedicine

End of Penis and scrotum > Infectious disorders > Scabies

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