I have had severe upper rhespiratory problems due to allergies for the past few days but today they re better but now after taking a claritin and a hot shower i have a blotchy red rash on my arms and legs it s not itchy but i m wondering what the cause mi

Viral? Allergic?: Blotchy appearing reddish rashes can occur when the blood flow in the tiny vessels at the skin's surface change, such as in an allergic rash, a viral rash, or in reaction to changes in skin temperature. Viral infections that cause cold symptoms and other symptoms can sometimes cause such skin patterns (fifth disease, caused by a virus, can cause reddish patterns). A doctor can evaluate if needed.