A pox virus behind 'water warts' usually leaves without any treatment at all
Around 122 million people had molluscum contagiosum in 2010, most of them children. The pearly, dimpled bumps come from a relative of the poxviruses, spread by touch and shared towels, yet they typically fade within a year without scarring, and studies struggle to show any treatment beats simply waiting.
The culprit is the molluscum contagiosum virus. Lesions show up roughly seven weeks after infection as small, dome-shaped, flesh-coloured or pink bumps, often 1 to 5 mm across, each with a dent in the middle. They may itch or feel sore. In children they tend to appear on the face, limbs, torso and armpits; in adults they usually cluster in the genital area, where the infection is treated as sexually transmitted.
It spreads easily: through skin contact in sport or sex, through contaminated objects, and by autoinoculation, when scratching a bump carries virus to fresh skin, something children do readily. A weakened immune system, atopic dermatitis and crowded housing all raise the risk. Under a microscope, infected skin cells are packed with clumps of virus particles known as Henderson-Patterson bodies, which shove each nucleus to the edge.
Single bumps can vanish within two months, and most outbreaks clear in six to twelve months, though reported durations range from six months to five years and last longer in people with weak immunity. Because of this, the usual first approach is to wait. A meta-analysis of randomised trials found no treatment clearly better than natural resolution in the short term. Options that are used include freezing with liquid nitrogen, scraping with a curette, which can scar, pulsed dye laser, and cantharidin, which studies judge effective and safe despite frequent blistering. Two large trials requested by the US Food and Drug Administration found imiquimod cream no better than a placebo.
Unlike herpes, the virus does not hide in the body: once every bump is gone, the person cannot pass it on and it will not return unless they catch it again. Reinfection, however, is possible. Hand washing and not sharing personal items are the recommended preventive steps. Cases in the United States have become more common since 1966.
Source: Molluscum contagiosum
