Dr Phil Kieran: My sporty teenager has an unusual summer rash

A one-off visit to the GP to confirm the diagnosis and get advice on preventing it would make sense. Picture: iStock 

For the second year in a row, my teenager has developed pale patches on his upper chest during the summer. It’s not itchy and becomes more obvious after he has been out in the sun and the surrounding skin tans. He’s a sporty boy, mostly playing soccer, and sweats heavily.

We will go through the two most likely conditions, neither of which is dangerous or worrying.

Vitiligo is when the immune system starts to attack the cells responsible for pigment in the skin. This can happen on any part of the body, but it most often starts on the more sun-exposed parts, such as the hands, lips, or in areas where the skin can become more irritated, like creases or folds.

The pale patches are usually very pale and will be pretty visible even when the rest of the skin isn’t tanned. There is frequently (in 20-30% of cases) a family history.

If what I have described is the case, it would be no harm to see your GP to have it confirmed and to see if any treatment is needed. The treatments for vitiligo are mainly focused on trying to prevent it from progressing.

The pattern your son has doesn’t really fit with vitiligo, though, so the more likely culprit is pityriasis or tinea versicolor. This is caused by a yeast called Malassezia. A fungus, it can also be responsible for dandruff, or a condition called seborrhoeic dermatitis, which affects the eyebrows and face.

This very common yeast is part of the normal skin microbiome, but for some people it can cause problems. It particularly causes versicolor changes in young men and those who sweat more, because the humid environment helps the yeast grow.

The condition usually clears up well, but it can recur, as appears to be the case for your son.

Most GPs can diagnose this on examination without the need for further tests. The treatment is usually either an anti-fungal cream or shampoo, or a shampoo containing selenium sulphide. Although marketed as shampoos, these products are often applied directly to affected areas of skin such as the chest and back before being rinsed off.

When the condition has settled, your GP will likely suggest regular use of a preventative shampoo to keep it under control. Some of these shampoos need to remain in contact with the skin for minutes at a time, which can be irritating for young men, for whom showering often doesn’t last more than a few minutes.

It doesn’t sound like there’s anything particularly worrying in your son’s case, and if it isn’t bothering him, he doesn’t really need to do anything about it.

If it is bothering him, though, a one-off visit to the GP to confirm the diagnosis and get advice on preventing it would make sense.

Alternatively, he could try a shampoo containing selenium sulphide and see if it settles down, reserving the GP visit in the event it doesn’t improve. If you go this route, make sure to follow the directions for the shampoo fully.

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