Question
Molluscum contagiosum
Answer
Molluscum contagiosum is a common, benign, self-limiting cutaneous viral infection caused by Molluscum Contagiosum Virus (MCV), a large, double-stranded DNA virus of the Poxviridae family.
Transmission: direct skin-to-skin contact, autoinoculation, fomites, and, in adults, sexual contact when lesions are genital/perigenital.
Clinical features: characteristic small, firm, dome-shaped, pearly papules with a pathognomonic central umbilication (dimpling); usually multiple, generally asymptomatic; in immunocompromised patients (advanced HIV/AIDS), lesions can be unusually numerous and widespread (“giant molluscum”), sometimes prompting HIV testing.
Laboratory diagnosis: usually a clinical diagnosis; if confirmation is needed, microscopy of expressed material or histopathology shows characteristic Henderson-Patterson bodies (large, eosinophilic intracytoplasmic inclusions) within infected keratinocytes.
Treatment: typically self-limiting, resolving spontaneously over months in immunocompetent individuals; physical destruction (curettage, cryotherapy) or topical agents (podophyllotoxin, cantharidin) can be used for cosmetic reasons or to reduce spread.