Hi
Welcome to the MedHelp forum!
This looks like urticaria or hives. The swellings or wheals produced after itching can be pale (of skin color) or red. Urticaria is usually triggered by allergens, such as drugs, foods, insect bites, inhaled substances, in response to sunlight, cold, heat, stress, exercise, or a viral infection. Other common allergens are pollen, mold, dust, pet dander, or cosmetics. Since you experienced an itch, just go over these possibilities in your mind. Something may strike you. In many cases, hives clear up themselves and don’t require diagnosis or treatment. However if they persists you may need to see a specialist called an allergist to determine what is causing the reaction.
Please consult your PCP for primary examination followed by proper referral. Take care!
It could be an allergy to clothes you wear reacting with your sweat.. I would recomment some allergy tablets piritons and some sudo cream which is anticeptic. Seeing your Doctor for further recommendations to see a dermatologists would be best.