Hi. Thanks for your query. Noted the history of irritation in the bums and under thighs, comes very often and after using some creams it gets temporary relief. Tried fourderm, gives temporary relief. Irritating for the last 3-4 years, consulted Dermatologist, getting darker and shows black patches and are embarrassing, wants permanent cure. The probable cause of such lesions is either allergic dermatitis or super-added fungal infection with loss of skin integrity allowing the infection of any sort to get settled not allowing the resistance of the skin to be healthy, hence the recurrent problems. I would advise you the following: Get blood test for CBC, sugar, immunity studies, Vitamin D as as per the clinical picture. Take Vitamin A and D in therapeutic dosages. Anti-fungal tablets if there is fungal skin infection. Multivitamins. Loose clothing. Avoid hot and humid atmosphere completely as it alone helps.