Skin pigmentation or changes in skin color can occur for a variety of reasons. Some causes are natural, while others may indicate an underlying medical condition.  Understanding the most common causes of skin pigmentation:

Hormonal changes

Hormonal fluctuations can cause an overproduction of melanin, often leading to melasma or chloasma. It appears as irregular, uneven patches of brown skin, usually on the face. The pigmentation usually disappears after pregnancy but can become permanent without adequate sun protection.

Inflammation

Inflammation of the skin can activate melanocytes, causing more melanin to be produced as part of the healing process. It usually appears as hyperpigmentation or dark spots at the site of inflammation. The dark areas usually disappear over time as the inflammation subsides. However, repeated scratching or irritating the skin can perpetuate pigmentation changes.

Melasma

Melasma, also called chloasma, appears as large patches of brown to gray pigmentation on the cheeks, nose, chin, and forehead. Sun exposure worsens this type of hyperpigmentation. Melasma usually goes away after giving birth or stopping taking hormones, but it takes a while to go away and can become permanent without sun protection.

Medicines

Some medications are associated with increased skin pigmentation as a side effect. Drug-induced hyperpigmentation usually resolves when the medication is stopped. Oral contraceptives, antimalarials, tetracyclines, chemotherapy, and some psychiatric drugs can cause overproduction of melanin. The discoloration appears as grayish-brown spots distributed on sun-exposed areas or all over the body.

Chemical exposure

Chemicals interacting with melanin production can cause skin discoloration through melasma-like spots, diffuse darkening, or uneven pigmentation. Hydroquinone, a common ingredient in skin lighteners, can paradoxically cause disfiguring dark defects called exogenous ochronosis when used for long periods. Arsenic, phenols, and some antibiotics are other chemicals associated with increased skin pigmentation. Pigmentation changes may be permanent if exposure is severe.

Injuries and scars

According to shakura review, changes in skin pigmentation often occur during the wound-healing process after surgeries, burns, trauma, cuts, abrasions, or other tissue damage. It usually goes away within a few months as the skin heals, but it can become permanent, especially if the inflammation returns or the skin is repeatedly irritated.

Skin aging

As skin ages, it accumulates damage caused by decades of sun exposure. Areas of uneven pigmentation or dark spots are characteristic of chronological and photoaging. Lentigines, called liver spots or age spots, gradually appear as flat, brown, or black spots on sun-exposed skin. They are formed when melanin and melanocytes clump together.

End

Consultation with a dermatologist makes it possible to make the correct diagnosis and prescribe treatment in case of unexplained changes in pigmentation.