Thanks for writing to us.
From the description provided i could think of few possibilitiesfungal infection
versicolor- again a superficial fungal infection which can present as hyperpigmented lesions. However commonly causes hypopigmented lesions
erythrasma- a bacterial infectionacanthosis nigricans
thickening and pigmentation of skin.
the exact diagnosis can only be reached either by consulting a dermatologist
near by or by using ASK A SPECIALIST feature of this website. Once the diagnosis has been confirmed, appropriate treatment can be provided.