What is pigmentation? Different types have different causes.

Pigmentation can be divided into many situations, and the causes of each type of pigmentation are different. For example, chloasma is caused by endocrine factors, while freckles are caused by genetic factors or sun exposure.

1. Melasma

It is caused by endocrine and other factors, and some causes are unknown. It is common in young women and worsens after sun exposure. It is often seen on the cheekbones, forehead, upper lip and around the eye sockets. Most of the spots are light brown with clear edges and are slightly symmetrical without any subjective symptoms.

2. Reil's melanosis

It may be related to certain contact substances, or it may be due to photosensitivity or unknown causes. It is more common in middle-aged women and its relationship with sun exposure is not obvious. It is common on the forehead, around the ears and sides of the neck. It is flaky light brown or light black spots with unclear boundaries, mild keratinization or thin scales on the surface, and no subjective symptoms.

3. Tar melanosis

It is more common in adult males due to long-term exposure to asphalt, petroleum and their petroleum products and is related to sun exposure. It manifests as diffuse light brown or dark brown spots on the face and exposed areas.

4. Freckles

Genetic factors, often occurring in childhood and aggravated by sun exposure. It manifests as yellow-brown or dark-brown spots on the face ranging in size from pinhead to rice-grain, with no subjective symptoms.

5. Ota disease

It is caused by genetic or congenital factors, occurs in childhood or adolescence, and has nothing to do with sun exposure. It appears as light blue or blue-black spots with clear edges on the collar, upper and lower eyelids and cheekbones.

6. Perioral lentigo

Also known as pigmentation-polyposis syndrome. Genetic factors, onset of the disease at an early age, unrelated to sun exposure. There are mostly brown-black spots on the lips, especially the lower lip, and oral mucosa.

7. Xeroderma pigmentosa

It is a genetic factor, the disease occurs since childhood, and worsens after sun exposure. Brown spots often occur on the face or neck, exposed areas of the hands and feet, accompanied by capillary dilation and atrophy, verrucous hyperplasia and hyperkeratotic rash. Cancer may occur.