Molluscum contagiosum is a common condition where small warty bumps (mollusca) appear on the skin. It is caused by a virus that can be passed on by skin contact or from contaminated towels, flannels, soft toys, etc. It is not serious and usually clears within 12-18 months without any treatment.
What does molluscum contagiosum look like?
The skin develops small lumps which are pearly-white or slightly pink. Each lump (molluscum) looks like a small wart and is round, firm, and about 1-5 mm across. A tiny dimple often develops on the top of each molluscum. If you squeeze a molluscum, a white cheesy fluid comes out. In most cases less than 20 mollusca develop. Sometimes many mollusca develop over various parts of the skin. They tend to occur in groups or clusters. Any part of the body can be affected but it is rare on the palms and soles.
For a list of websites that contain pictures of skin conditions, including molluscum contagiosum, see www.patient.co.uk/showdoc/1097/
What causes molluscum contagiosum?
It is caused by a virus which can be passed on by skin-to-skin contact. You can also be infected by touching things that have been contaminated by the virus. For example, by sharing towels, flannels or soft toys that have been used by someone who has molluscum contagiosum. Once one area of skin is affected the rash can spread to other areas of your skin. However, most people are resistant (immune) to this virus. Therefore, most people who come into contact with affected people do not develop molluscum contagiosum. The risk of getting molluscum contagiosum is increased by poor hygiene and in hot climates. It is also more common in people whose immune system is not working properly.
Molluscum contagiosum can affect anyone of any age. However, about 8 in 10 cases occur in people under the age of 15. Most occur in children aged 1-4 years.
How does molluscum contagiosum develop?
The mollusca (the warty bumps) develop 2-8 weeks after you become infected with the virus. Typically, each molluscum lasts about 6-12 weeks, crusts over, and then goes. However, new ones tend to appear as old ones are going as the virus spreads to other areas of skin. Therefore, crops of mollusca may appear to come and go for several months.
It commonly takes 12-18 months before the last of the mollusca goes completely. Occasionally, the condition lasts longer than two years - sometimes as long as five years. For some people, the main concern is that the mollusca can look unsightly. However, most children are not bothered by it.
Is molluscum contagiosum serious?
Mollusca are not usually itchy, painful, or serious. A scar is not usually left when they go, but sometimes a tiny pitting (indented) scar remains. In a few people the skin looks lighter where each molluscum had been. Occasionally, the skin next to a molluscum becomes infected with bacteria. This can be treated with antibiotics. Rarely, a molluscum on an eyelid causes eye inflammation. (See a doctor if any eye symptoms develop related to a molluscum.) After an episode of molluscum contagiosum has cleared away, you will normally be immune to the virus and further episodes only occur rarely.
If you develop a very large number of mollusca (hundreds) or the mollusca are larger than normal, it could be a marker of an underlying immune deficiency. For example, as a consequence of chemotherapy or HIV infection. This may need specialist assessment.
Can infection with molluscum contagiosum be prevented?
The chance of passing on the molluscum contagiosum virus to others is small, and it is not serious anyway. Therefore, there is no need to keep children with molluscum contagiosum off school, or away from swimming pools, gyms, etc, or away from other children.
To reduce the chance of passing it on to others, it is sensible not to share towels, clothes, soft toys, or bath water. Also, try to avoid skin-to-skin contact with other people (for example, by covering affected areas with clothing). Encourage children not to scratch the mollusca, as this may increase the risk of spreading the rash to other areas of the skin. Molluscum contagiosum is contagious until the last molluscum has gone.
What is the treatment for molluscum contagiosum?
It is usually best not to treat, particularly in children, because:
- The mollusca will usually go away without treatment within 12-18 months. Having the rash does not limit your activities such as going to school, sports, swimming, etc.
- Many of the treatments can be painful (such as liquid nitrogen).
- Some treatments have a risk of burning the surrounding skin.
- All treatments have a small risk of scarring the skin. Scarring rarely occurs if the mollusca are left to go away on their own.
Some people request treatment if the rash is unsightly
- One treatment often used is to burst the mollusca with a sharpened orange stick or sterile needle.
- In some cases, other treatment options that may be considered by a doctor or nurse (not to be tried at home!) include: freezing treatment with liquid nitrogen; a hot metal stick (diathermy) to burn off mollusca; scraping the mollusca off with an instrument called a curette; touching the mollusca with various chemicals such as phenol (a strong acid). These treatments can be painful, and are not usually done on children.
- A cream called imiquod is sometimes used if no other treatment works and the mollusca are very widespread. This usually happens in people who have problems with their immune system.
Further reading & references
- Management of molluscum contagiosum, British Association for Sexual Health and HIV (2007)
- Molluscum contagiosum, Clinical Knowledge Summaries (2008)
- Stulberg DL, Hutchinson AG; Molluscum contagiosum and warts. Am Fam Physician. 2003 Mar 15;67(6):1233-40.
- Kauffmann CL et al; Mollluscum Contagiosum, eMedicine, Jul 2010
|Original Author: Dr Tim Kenny||Current Version: Dr Laurence Knott|
|Last Checked: 25/11/2010||Document ID: 4425 Version: 39||© EMIS|
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