A 17-year-old boy comes to the office due to a rash. He has had a progressive papular rash involving the trunk, neck, upper arms, and genital area for 8 weeks. The lesions are mildly pruritic, but there are no other associated symptoms. Past medical history is notable for mild intermittent asthma and childhood eczema. The patient also was treated empirically a year ago for chlamydia after exposure to an infected sexual partner. He is up to date with recommended vaccinations. Vital signs are normal. Examination shows normal growth and body habitus, with appropriate sexual development for age. Dermatologic examination shows widespread firm, dome-shaped, flesh-colored papules with central umbilication. This patient's rash is most commonly associated with which of the following conditions?

Question

A 17-year-old boy comes to the office due to a rash.  He has had a progressive papular rash involving the trunk, neck, upper arms, and genital area for 8 weeks.  The lesions are mildly pruritic, but there are no other associated symptoms.  Past medical history is notable for mild intermittent asthma and childhood eczema.  The patient also was treated empirically a year ago for chlamydia after exposure to an infected sexual partner.  He is up to date with recommended vaccinations.  Vital signs are normal.  Examination shows normal growth and body habitus, with appropriate sexual development for age.  Dermatologic examination shows widespread firm, dome-shaped, flesh-colored papules with central umbilication.  This patient's rash is most commonly associated with which of the following conditions?

Quizplus · Accepted Answer

11ec25c8_d383_0a11_bc81_930115fa3206_MD0003_00 Molluscum contagiosum (MC) is a skin infection caused by a poxvirus. It is characterized by small, pruritic, skin-colored papules with umbilicated centers. Children are most commonly affected, but adolescents and adults also can develop MC. Transmission occurs through skin-to-skin contact or via contaminated fomites, with subsequent autoinoculation to additional sites. In children, lesions commonly appear on the extremities, face, or trunk; in adults, sexual transmission may lead to lesions on the lower trunk and anogenital region. The diagnosis is primarily clinical and based on the typical appearance of the lesions. MC is self-limited (resolution within 6-12 months), but treatment with curettage, cryotherapy, or topical agents (eg, podophyllotoxin) may be considered to prevent further spread, reduce symptoms, or improve cosmesis. Patients with impaired cellular immunity (eg, HIV disease) may have a prolonged course with widely distributed papules, facial involvement, and lesion counts numbering in the hundreds. HIV testing should be considered for patients with MC, especially if they have large (>10 mm), numerous, or widespread lesions. (Choice B) Hypersensitivity rashes caused by circulating autoantibodies may be of type II (antibody-dependent cellular cytotoxicity) or type III (immune complex deposition) variety. Type II rashes are more likely to manifest as blisters or bullae (eg, pemphigus vulgaris, bullous pemphigoid) than papules. Type III rashes tend to be more erythematous and maculopapular. (Choice C) The complement system is involved in defense against pathogenic bacteria. For example, C3 deficiency predisposes to pyogenic bacterial respiratory tract and sinus infections, and C5-C8 deficiencies predispose to recurrent Neisseria infections. Complement deficiency does not increase the risk of MC or other viral infections. (Choice D) Disorders of phagocytosis (eg, chronic granulomatous disease, Chédiak-Higashi disease, Job syndrome, defective leukocyte adhesion proteins) present with severe pyogenic bacterial infections. Innate immunity against viruses is less affected. (Choice E) Selective IgA deficiency can predispose to recurrent respiratory infections and chronic giardiasis. It will not increase the risk of MC. Educational objective: Molluscum contagiosum is characterized by firm, flesh-colored, dome-shaped, umbilicated papules. Patients with impaired cellular immunity (eg, HIV disease) are at risk for more severe, widespread disease. References: Molluscum contagiosum virus infection. (http://www.ncbi.nlm.nih.gov/pubmed/23972567)

A 17-Year-Old Boy Comes to the Office Due to a Rash