# Molluscum Contagiosum > Molluscum contagiosum in NEET-PG Dermatology: poxvirus, Henderson-Patterson bodies, umbilicated papules, cantharidin and giant lesions in HIV. - Canonical URL: https://prepelephant.com/topics/neet-pg/dermatology/molluscum-contagiosum - Exam / course: NEET-PG · Subject: Dermatology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Molluscum Contagiosum", PrepElephant, https://prepelephant.com/topics/neet-pg/dermatology/molluscum-contagiosum ## Direct answer Firm, pearly, dome-shaped papules of 2-5 mm with pathognomonic central umbilication announce molluscum contagiosum, a benign poxvirus (MCV) infection spread by skin-to-skin contact, shared towels, scratching (auto-inoculation in Koebner-like streaks) and, in adults, sexual transmission. Four viral types exist; MCV-1 dominates childhood infection while MCV-2 is proportionally commoner in adults with genital lesions and HIV. Expressing the core yields the molluscum body — the Henderson-Patterson body, a keratinocyte distended by eosinophilic cytoplasmic inclusion bodies pushing the nucleus aside. Most infections in immunocompetent children self-resolve within months to a couple of years, so watchful waiting is legitimate; treatment options include cantharidin application, curettage, cryotherapy and potassium hydroxide. Facial and genital clustering in adults, giant lesions, or hundreds of lesions refractory to therapy should prompt HIV testing, since widespread molluscum is a cutaneous marker of advanced immunosuppression. ## What you must remember - **The lesion at a glance:** pearly, dome-shaped, 2-5 mm papule with central umbilication and a white keratinous core that expresses as a curd-like plug. - **The histology eponym:** Henderson-Patterson (molluscum) bodies — large eosinophilic intracytoplasmic inclusions filling infected keratinocytes; the crateriform architecture on section clinches diagnosis. - **Epidemiological split:** MCV-1 causes most childhood cases; MCV-2 is over-represented in adult genital molluscum and HIV — genotyping is academic, but the epidemiology points testing. - **Pattern reading:** children — face, trunk, flexures, spread by scratching and aggravated by atopic dermatitis (impaired barrier, molluscum dermatitis around lesions); adults — genitals, abdomen, inner thighs as a sexually transmitted infection; check for other STIs per syndromic practice. - **The HIV flag:** giant molluscum (over 1 cm), facial clustering, or lesions refusing all therapy in an adult — order an HIV test; lesions typically regress once antiretroviral therapy restores immunity. - **Treatment ladder:** watchful waiting (self-resolution in the majority within 6-12 months); cantharidin 0.9% paint ("apply and go," blister-inducing); mechanical curettage; cryotherapy; potassium hydroxide 5-10%; imiquimod is now discouraged in young children (systemic absorption reports, weak evidence). - **Complications to mention:** molluscum dermatitis (eczematous halo), secondary bacterial infection, transient pitted scarring after inflammation, and conjunctivitis with lid-margin lesions — ophthalmology referral for periorbital disease. - **Differential in the adult with umbilicated lesions:** basal cell carcinoma, cryptococcosis and other disseminated fungal infections in immunosuppression, keratoacanthoma — biopsy umbilicated nodules that ulcerate or bleed. ## Managing the child, the adult, and the immunosuppressed A mother brings a 4-year-old with eczema and twenty mollusca clustered around the axillae and elbows, with an eczematous halo around several. The first intervention is managing expectation: these will clear on their own in most children within a year, and the surrounding dermatitis is treated with emollients and a mild topical steroid to break the itch-scratch-spread cycle. If she wants active treatment, cantharidin painted in clinic with a "no touching, wash in 4-6 hours" instruction, or quick curettage under topical anaesthesia, are the practical Indian options; painful cryotherapy in a pre-schooler buys trauma, not clearance. The swim class and shared towels are paused, not the child's schooling. The adult consultation is a different consultation. Umbilicated papules on the lower abdomen, genitals and inner thighs constitute an STI: screen for HIV and syphilis, examine the partner, and treat the lesions — curettage or cryotherapy for the accessible few, imiquimod for recurrence-prone genital disease. When the same adult returns with giant, coalescing facial lesions unresponsive to three destructive attempts, the diagnosis outranks the treatment: test for HIV, and if positive, expect resolution with effective antiretroviral therapy rather than escalation of local torture. In the transplant patient on immunosuppression, similarly, modest molluscum is monitored and individual lesions treated, but the driver is the net state of immunosuppression. ## Where the exam aims Two facts dominate the paper: the Henderson-Patterson body as the histological eponym, and the poxvirus family of the causative agent. The clinical photograph question shows pearly umbilicated papules and tests either the diagnosis or, in an adult face, the "next investigation" — HIV serology. Candidates lose marks by treating every molluscum: the stem with "healthy child, few lesions, parent anxious" wants reassurance and watchful waiting among the options. Finally, know the cantharidin concept — a blistering agent applied without occlusion and washed off at home — because mechanism-based questions on "paint, not pop" therapy appear as single-best-answers. ## Frequently asked questions ### What are Henderson-Patterson bodies? Large eosinophilic intracytoplasmic poxvirus inclusions filling keratinocytes within the crateriform molluscum lesion — the diagnostic histological finding. ### How does molluscum contagiosum spread in children? By direct skin contact, auto-inoculation through scratching, shared towels and swimming pools, with atopic dermatitis increasing density and spread. ### When should molluscum contagiosum prompt HIV testing? Giant lesions (over 1 cm), extensive facial disease in an adult, or failure to respond to therapy — all markers of cell-mediated immunodeficiency. ### Which treatments are preferred in young children? Watchful waiting first; cantharidin application or quick curettage when treatment is desired, with imiquimod avoided in early childhood. ### What is molluscum dermatitis? An eczematous halo surrounding lesions, common in atopic children, treated with emollients and mild topical steroids to interrupt scratching and dissemination.