Rashes that appear over the folds are generally related to allergic disorders inherited from the gene if any family members have allergic disorders like rhinitis , eczema or asthma . As these conditions are recurrent in nature, one needs to learn about the triggers and how to manage it well. In case if skin allergies one needs to avoid harsh soaps, excessive dryness, synthetic fabrics, wollen , pollens , dust etc. Dermotologist would advise few regular skin friendly medicines which can control the condition.