Irregular Pigmentation Home A-Z Health Information Health Library A-Z Irregular Pigmentation Overview Pigmentation involves skin darkening caused by excessive melanin production. Types Hypopigmentation: It is marked by a lighter skin tone in the affected area.Hyperpigmentation: It is marked by a darker skin tone in the affected area. Symptoms Dark or lighter patches or spots on the skin. Causes Sun exposureHormonal changesCertain diseasesInflammation Diagnosis Skin examination and medical history by a dermatologist. Treatment Topical agentsChemical peelsLaser therapyPRP therapy, depending on the condition and underlying cause