Melanin is a pigment produced in the skin cells that causes skin coloration. An amino acid, tyrosine, is converted to melanin through a series of complex chemical steps in the skin cells. This process may be affected by heredity, heat, trauma, solar or ionizing radiation, heavy metals, and other factors. Pigment production and distribution in the body is regulated in part by hormones. Changes in any of these factors can result in hyperpigmentation (increase in pigment production), hypopigmentation (decrease in pigment production), or both. The changes may be temporary or permanent. Pigment changes can be primary (existing as a separate disorder) or secondary to (resulting from) other disorders.
A person's degree of skin pigmentation determines, to some extent, the various dermatological diseases to which a person may be susceptible. Lighter-skinned people are more sensitive to sun exposure and damage and the subsequent development of skin cancer (basal cell carcinoma, squamous cell carcinoma and malignant melanoma). Excessive sun exposure is a risk factor even for darker-skinned people.
Generally, pigment changes are cosmetic and do not affect physical health. However, psychological stress can occur because of pigment changes. Some pigment changes may indicate a risk for other disorders.
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