See Photo Sensitivity.
An exaggerated tendency to easy sunburn
This refers to a situation where the sufferer is unduly sensitive to sunshine and can come out in either a red rash or even a severe eczema only at the sites of sunshine exposure. For example, where the skin is protected by layers of underwear, it is common for the underlying skin to be completely normal but exposed skin to be very severely infected. Various rare diseases can cause photosensitivity but the commonest cause is taking oral medication such as antibiotics or diuretics (water tablets). Occasionally, skin surface creams can also cause photosensitivity and some patients even suffer this reaction from sunscreens.
Particulary for children an expert consultation and preventative advice are really important. You can get a consultation here.
by Dr John Ashworh