Skin pigmentation disorders affect the color of your skin. Excess of melanin forms deposits that cause the brown pigments. Melanin is responsible for giving skin color. Specific conditions that make skin darker are: hyperpigmentation, acanthosis nigricans, sun exposure, pregnancy, melasma, solar lentigenes. On the other hand, decrease in melanin causes certain conditions like vitiligo which appears as patches of light skin. Other infections, burns and blisters may also cause lighter skin.