Y do i have hives?

I've  had hives since the middle of the summer. I don't know what caused them and I don't know how to get rid of them. I was tanning in a tanning bed and going to lakes so I don't know if it's from any of that. One day I noticed them on my neck when i was getting on my swim suit to go to the lake. I thought something had bitten me. I put my sister's sun block on my shoulders, arms, stomache and chest areas. The next day I had hives all over the places i put the sun block. ???  I used cortisone and thought they had gone away. So I tried to use my treadmill like I had been doing before I got the hives and when I got hot and sweaty they re-appeared. So I quit using my treadmill again. Then once again I thought they were gone and I tried going to the tanning bed again and they came back again. I guess they never fully went away...??? Does anyone know what could be going on. I changed my shampoo, body wash, and laundry detergent. I can't figure it out. I didn't eat anything different that I know of to cause these hives. Has this happened to anyone else out there?? Could i be allergic to my own sweat? Lol.

[lauraedwards]

I also have victoria's secret bras, but the hives started on my neck so that couldn't be it could it???

[Bhupinder Kaur, MD]

Hello,

Without examination,confirmation of a diagnosis is tough,but it can be hives,sweat urticaris or contact dermatitis.

Hives (medically known as urticaria) are red, itchy, raised areas of skin that appear in varying shapes and sizes. They have a tendency to change size rapidly and to move around, disappearing in one place and reappearing in other places, often in a matter of hours.

Many cases of hives are "idiopathic," meaning no cause is known. Others may be triggered by viral infections or medications.

The mainstay of treatment of hives is antihistamine which may be necessary for prolonged periods (in excess of 6 weeks).Non-sedating antihistamines such as Cetirizine and Loratadine(Claritin) may be needed to get symptom relief. Sedating antihistamines such as Chlorphenamine(benadryl)are used at night to get urticaria control. 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. Pls do not use any cosmetic product,maintain a good hygiene and apply calamine lotion on this rash.It will help in soothing the skin.Wear cotton and free flowing clothes and try keeping cool as urticaria may tend to flare up in warmer conditions. In particular, keep the bedroom cool at night.

If the symptoms persist then pls get it evaluated from a dermatologist.
Hope it helps.Take care and pls do keep me posted if you have any additional queries.