Question:

Question: A 46-year old clerk complained of asymptomatic papular rash at the pubic region, limbs and trunk for the past three months. He found that the number of these papules increased gradually and he had attempted self treatment by trying various topical creams without response. He also had mild malaise and low grade fever recently and he was admitted into hospital for investigation of weight loss and prolonged fever. On examination, there were multiple pearly shining surface papules scattered unevenly at the arms and few on the trunk. He claimed to have good health in the past.

Answer: C. Molluscum contagiosum

This patient had blood test screening for HIV and was found to be positive with low CD4 count. His skin papules were clinically compatible with molluscum contagiosum (MC). MC is caused by a large DNA poxvirus. It occurs by close skin to skin transmission and hence is found most often in children or as a sexually transmitted disease in adults. It can be disseminated in patients with altered immune status as in this patient. Characteristic lesions are 1 to 3 mm umbilicated papules that usually commence in a cluster and with time will spread to other areas. The umbilication of the lesions may not be apparent and it may appear vesicular though no fluid drains out when lesions are punctured. Instead, some cheesy white material can be expressed by superficial curettage of the papules. In HIV positive patients, MC can present as larger nodules and can be more deeply seated on the skin. In immuno-suppressed patients, the cutaneous manifestation of some opportunistic infections e.g. Cryptococcus, histoplasmosis, coccidiomycosis are known to mimic this problem. Curettage of the lesions is a rapid way to clear the MC lesions. Cryotherapy, applications of salicylic acid or other chemical peeling agents, and carbon dioxide laser abrasion are all effective treatments. Topical imiquimod cream has recently been reported to be of benefit in both immuno-competent and HIV patients.

Verruca vulgaris or common wart has a rough or hyperkeratotic surface. Lesions are not cystic or vesicular. Palpation of common wart will convey a firm and warty sensation. Differentiation on clinical grounds alone is easy and adequate. Epidermoid cyst is usually characterized by a central punctum and is rarely disseminated and multiple except in patient of Gardner's syndrome. Furthermore, epidermoid cyst is more deep seated compared to that of MC. Lichen nitidus manifests as multiple, small pinhead sized or 1-2 mm in size, round, flat-topped, shiny flesh-coloured papules on the extremities, abdomen or penis. It is considered to be a variant form of lichen planus but it is usually non-itchy and is often self limiting. Hence usually no treatment is required.