Q. I have vitiligo, a long-term skin problem that produces white patches of de-pigmentation. Can you tell me which fake tan is best to use? I need one that doesn't work on your own melanin. A. While we understand your concern, in fact DHA (dihydroxyacetone) - the active ingredient in sunless tanners - doesn't actually stimulate melanin production from your own melanocytes, which are found in the basal layer of the epidermis.

DHA, itself a colourless 3-carbon sugar acts on proteins in the very top layer of the skin – the stratum corneum - to produce pigments called melanoidins, which produces a skin-darkening effect.

Both NHS Choices and Vitiligo Support International recommend that you use the self-tan of your choice. The tricky bit is to match the white patches of vitiligo with the rest of your skin. So experts suggest applying self-tan all over then taking a foundation brush and colouring in the patches.   (NB Tinted self-tan is obviously much easier to work with as you can see where it goes.) Instead of self-tan, you may want to try an instant bronzer, although this will wash off and need to be reapplied the next day.

If you have a spray tan professionally applied at a salon, they can apply tan top to toe (always shield eyes, nose and mouth) then pinpoint the white patches and even them up. (St Tropez comes top of most salon tanners’ wish list, see here for details.)

You can also find waterproof camouflage make-up that last up to four days on your body, which may be available on prescription. Discuss this with your health professional. More information from Changing Faces Skin Camouflage Service - click here.

You may never be able to camouflage the patches totally by these means but you can end up with a much more even skintone.

Finally, one word of caution: self-tanners give you absolutely no protection against UV rays and, by definition, the de-pigmented patches of vitiligo are vulnerable. So you must be sure to apply SPF30 regularly whenever you are exposed to the sun and top up every two hours or so. Also, do not use sunbeds.

For best products, see the ongoing instalments of our Summer Sun Guide on www.beautybible.com - we'll be looking at the winning self-tanners in more depth, but these include TanOrganic Self-Tanning Oil and Omorovicza Glam Glow.

TanOrganic Self-Tanning Oil/£24.99 for 100ml at www.feelunique.com - buy here

Omorovicza Glam Glow/£35 for 150ml at www.selfridges.com - buy here