Molluscum contagiosum: symptoms, treatment and how long it lasts

Treatment is not usually needed in people with healthy immunity, especially when disease is mild, the spots do not bother the person, or they are on delicate areas such as the face or groin of young children (NICE). The NHS says it is rare to need treatment, but a GP may suggest antibiotics if spots become infected and a steroid cream for itchy, dry or sore skin, such as an eczema rash caused by the spots.

If active treatment is chosen, the British Association of Dermatologists lists topical therapies such as salicylic acid and potassium hydroxide, which irritate the bumps so the immune system recognises the virus; freezing with liquid nitrogen at intervals; and scraping them off (curettage) after local anaesthetic. A hospital eye specialist can treat spots on the eyelids. The leaflet is frank that many treatments are painful, some may raise the risk of scarring, and there is no research evidence that one treatment is better than another.

The NHS says a GP may refer you to a specialist if you have lots of spots or the spots are having a big impact on your life, if they are near the eyes, eyelids or genitals, or if you have a weakened immune system. NICE adds that eyelid-margin or eye lesions with a red eye need urgent ophthalmology referral.

Molluscum contagiosum is a viral infection of the top layer of the skin. NICE Clinical Knowledge Summaries describe the cause as the molluscum contagiosum virus, which belongs to the poxvirus family. The condition is common, although the true number of cases is uncertain because many people never seek care.

It is mostly a childhood condition. NICE notes the highest incidence is in pre-school children aged 1 to 4 years, and the NHS says that although it is more common in children, anyone can get it. The British Association of Dermatologists adds that it is most common in children and young adults.

The infection is described as generally harmless and self-limiting. For most people the spots are a cosmetic and practical nuisance rather than a health threat.

The NHS describes the typical spot as 2 to 5mm wide, raised and dome-shaped, with a shiny white dimple at the centre. The British Association of Dermatologists gives a slightly wider range of 2 to 6 mm, notes that occasional spots can reach 20 mm, and says they may be skin-coloured, red or pink, or darker brown on darker skin. They are usually not itchy unless they become inflamed.

Where they appear depends on how the infection was caught. The NHS says children often have spots on the body and in or around skin folds such as the groin, behind the knee and the armpits. In adults, when the infection is passed on through sexual contact, spots may be on the lower tummy, genital area and thighs. NICE adds that rarely the palms, soles, inside of the mouth and eyelids can be affected.

• Often only a handful of spots; the British Association of Dermatologists says usually fewer than 20.

• Spots can sit in clusters.

• Dry, red eczema-like patches can appear around them.

• An inflamed spot can look like a boil, which is one reason a clinician may want to look.

• After they clear, the skin may look paler, pinker, purplish or darker for a while before returning to its usual tone.

NICE describes transmission by direct contact with infected skin, whether sexual, non-sexual or by spreading it from one part of your own body to another, and indirectly through items such as shared towels and flannels. The NHS says the chance of passing it on during normal activities is small, so most people can carry on as usual, but it still advises sensible precautions.

The NHS says the spots are usually harmless and should clear up within 18 months without needing treatment. The British Association of Dermatologists quotes 6 to 18 months, and notes that new spots can appear while older ones clear, so it can look as though it is not improving.

NICE lists scarring, conjunctivitis, keratitis, bacterial infection of the spots and psychological distress as possible complications. The last is worth taking seriously: visible spots can bother children and adults, particularly when they linger. For most people the spots go away within the time frames the NHS and the dermatologists quote, even if that is longer than hoped.

The NHS says it is more common in children, although anyone can get it, and that children often get spots on the body and in or around skin folds, such as the groin, behind the knee and the armpits. NICE notes the highest incidence is in pre-school children aged 1 to 4 years.

The British Association of Dermatologists says children with molluscum do not need to be kept off school. Covering the spots, using their own towel and flannel and not squeezing or scratching them helps limit spread. The NHS suggests keeping spots covered with waterproof bandages for swimming. Keeping skin moisturised and treating any eczema may help, because the dermatologists note molluscum is commonly seen in people with eczema.

The British Association of Dermatologists explains that molluscum is commonly seen in people with eczema and can be widespread, because dry, cracked skin lets the virus in more easily. Gentle, regular moisturising and treating eczema flares remain relevant, and a GP can advise on how to manage the two together.

People with a weakened immune system may have more spots. The NHS says they may get spots on the face or around the eyes, or have lots of spots or bigger ones, and the dermatologists name HIV and treatments that suppress immunity as examples. NICE advises urgent referral to an HIV specialist for people with HIV and extensive lesions.

Usually no tests are needed. The British Association of Dermatologists says a healthcare professional can normally recognise the bumps by sight, and a skin biopsy is an option only if there is doubt. NICE lists warts, milia, lichen planus and some other skin conditions as the look-alikes a clinician considers.

The NHS directs people to check with a GP if they are not sure the spots are molluscum, which is sensible because other rashes can resemble it. For adults with spots in the genital area, NICE says referral to genito-urinary medicine is appropriate because screening for other sexually transmitted infections may be needed.

The NHS says to see a GP if you are not sure your spots are caused by molluscum contagiosum, if the spots are very itchy, painful, swollen or covered with crusts, if you have spots near your eyes or genitals, or if you have a weakened immune system and think you may have molluscum.

A GP may refer you to a specialist if there are lots of spots or they are having a big impact on your life, if spots are near the eyes, eyelids or genitals, or if you have a weakened immune system, for example if you are having chemotherapy or have HIV (NHS). NICE says that spots on the eyelid margin with a red eye need urgent ophthalmology referral. Molluscum is not usually an emergency, but a rapidly spreading red, hot or painful area needs prompt medical review.

On the NHS, molluscum is usually recognised by a GP or practice nurse and managed with reassurance and self-care. Referral to dermatology, ophthalmology or sexual health services follows the criteria above. Because many treatments are painful and are not proven to work better than waiting, active treatments such as cryotherapy or curettage are typically offered selectively.

Some people choose a private dermatologist for faster treatment of spots. Ask what the options are, how painful they are in children, what the chance of scarring is, and what the total cost would be before agreeing, bearing in mind that the British Association of Dermatologists says no one treatment has been shown to be better than the others.