unexplained hives

I recently layed out in the sun for no more than 15 minutes when I developed a large patch-like rash/hives

on my upper legs. It itched alittle, not very much. And it went away within an hr. The weird thing is I was

wearing shorts that were knee-length! I am going to the beach in 1 month. What is it! and what do I need to do!

[29sillygirl]

All I know is that skin can react with hives when you are first exposed for any length of time.  I used to have about 48 hours of itchy hives all over before my body adjust to the sun at beach.  It went away and I baked away with no more hives.
Now, of course, my dermatologist needs to see me semi-annually to make sure I don't have skin cancer:).    BTW: I used calamine lotion for itch.

[Bhupinder Kaur, MD]

Hello,
It can be due to solar dermatitis or solar urticaria. It is the development of hives minutes after exposure to the sun, which resolve in less than 1 hour.

Apply a good sunscreen with minimum spf 30 atleast half an hour before going out in the sun. You can take non-sedating antihistamines such as Cetirizine or Loratadine(Claritin) when the rash appears. Short courses of oral cortisone or steroids are taken for short periods (one to three days) to settle more severe symptoms . You may take Vitamin C along with the prescribed treatment. Vitamin C is a general anti-allergy supplement. Also apply calamine lotion and a mild steroid cream like dermacort on the rash.

It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.