Hello. Thank you for writing to us This could be a superficial fungal infection, pityriasis versicolor. This infection is caused by a yeast, malassezia furfur. The yeast may produce small brown, scaly spots on upper back and shoulders. Sun exposure makes them appear darker as compared to surrounding normal skin. The yeast feeds on oil and therefore it tends to affect these areas as these areas are rich in sebaceous glands. Diagnosis is usually obvious clinically and it can also be confirmed with a KOH wet preparation to look for fungal elements. Treatment of a confirmed fungal infection is by topical antifungal lotions for 2 weeks. A single dose of an Oral antifungal e.g fluconazole is also effective. I suggest that you visit a specialist in your region for a confirmatory diagnosis as well the needful. Regards