Dr. Macrene's DDD:  Drugstore, Device & Dermatology Causes of Skin Discolorations: Brown spots, discolorations or uneven skin tone may be caused by a number of factors, including sun exposure, melasma, post-inflammatory hyperpigmentation, scars and genetics. Sun exposure and traumas may make skin look discolored, blotchy, uneven, dull or sallow. Melasma is caused by...