Hello, I can understand your concern for red dotted rash over body. After reading your it appears that you are suffering from Allergic contact dermatitis . There can be multiple factors producing this condition which are included in day to day life and some times it is really difficult to find one exact cause. In your case you are correlating it with exercises, hot climate,spicy food. So it is better to stay away from the offending factors. The long term effective treatment for this is by oral anti histamine like loratadine under medical advise. It is one of the drug which is not having any side effects and can be taken for long term usage. Do not scratch or rub the skin as it can lead to further aggravation. If the rash increases then can meet a dermatologist for further suggestions. Take care.