Hello!
Any allergy, infection can lead to red rashes on the body. You probably seem to be suffering from hives or urticaria.Hives is usually an allergic reaction to food or medicine. During an allergic reaction substances like histamine and other substances are released in the blood stream. Insect bits, medications, pollen all can trigger hives. Take antihistaminic for relief in symptoms. Consult a dermatologist and confirm the diagnosis. Do keep us posted.
Take care and regards!