The image displays multiple discrete skin lesions on the thigh of a child. Which of the following is the most likely diagnosis?

Explanation

## Image Findings * Multiple, discrete, skin-colored to pinkish papules are present on the thigh. * Many of these papules exhibit **central umbilication**. * The lesions are scattered over the affected area. * The surrounding skin appears normal. ## Diagnosis **Key Point:** The presence of multiple, discrete, skin-colored to pinkish papules with **central umbilication** is pathognomonic for **Molluscum contagiosum**. Molluscum contagiosum is a common viral skin infection caused by the **Molluscum contagiosum virus (MCV)**, a member of the **Poxviridae family**. It typically presents as small, firm, dome-shaped papules with a characteristic central depression or umbilication. These lesions are often seen in children and are spread by direct skin-to-skin contact or fomites. The lesions are usually asymptomatic but can sometimes be itchy or inflamed. ## Differential Diagnosis | Feature | Molluscum Contagiosum | Verruca Vulgaris (Warts) | Herpes Simplex Infection | Varicella (Chickenpox) | | :------------------ | :-------------------------------------------------- | :----------------------------------------------------- | :------------------------------------------------------- | :------------------------------------------------------- | | **Morphology** | Dome-shaped papules with central umbilication | Hyperkeratotic, rough, exophytic papules/plaques | Grouped vesicles on an erythematous base, often painful | Macules, papules, vesicles, pustules, crusts in various stages (dewdrop on a rose petal) | | **Etiology** | Molluscum contagiosum virus (Poxvirus) | Human papillomavirus (HPV) | Herpes simplex virus (HSV) | Varicella-zoster virus (VZV) | | **Distribution** | Anywhere, common on trunk, extremities, face, groin | Common on hands, feet, knees, elbows | Localized, often perioral, genital, or specific dermatome | Generalized, centripetal spread | | **Key Feature** | Central umbilication | Rough, verrucous surface | Grouped vesicles | Polymorphous rash (lesions in different stages) | ## Clinical Relevance **Clinical Pearl:** Molluscum contagiosum is highly contagious, especially among children, and can spread through direct contact, shared towels, or swimming pools. Autoinoculation is also common, leading to new lesions in different areas. ## High-Yield for NEET PG **High-Yield:** Molluscum contagiosum is caused by a **DNA poxvirus**. The characteristic central umbilication is due to the viral inclusion bodies (Henderson-Paterson bodies) pushing the epidermis inwards. **Key Point:** While typically self-limiting, treatment may be considered for cosmetic reasons, to prevent spread, or in immunocompromised individuals. Common treatments include cryotherapy, curettage, topical retinoids, or imiquimod. ## Common Traps **Warning:** Differentiating molluscum contagiosum from warts can be tricky. Remember that warts are typically rough and hyperkeratotic, lacking the smooth, dome-shaped appearance and central umbilication of molluscum lesions. Varicella presents with vesicles, not solid papules, and a generalized distribution. ## Reference [cite:Fitzpatrick's Dermatology in General Medicine, 9th ed., Ch 200]