Hi, Your condition seem to be Urticaria and very probably solar urticarial , when occurring only on skin exposed to the sun. You must distinguish carefully your signs, in urticarial appear red, raised palpable wheals, frequently circular form, accompanied by itching. Also may appear dermatographism when urticarial lesions resulting from light scratching. If you develop above mentioned signs and symptoms then you can think about urticaria. In such case you need avoid sun exposure, take antihistaminic medication(H1, H2, ) and in sever case glucocorticoids. Would be preferable if you will consult Dermatologist. Take care.