Skin pigmentation disorder affects the color of the skin. The skin gets its color from a pigment called melanin. When the cells become damaged or become sick, the production of melanin is affected. Some pigmentation disorders affect only certain regions of the skin. Others affect the entire body.
If the body produces too much melanin, the skin darkens. Pregnancy, Addison’s disease and exposure to the sun can darken the skin. If the body produces very little melanin, the skin becomes clearer. Vitiligo is a condition that causes depigmentation of the skin. Albinism is a genetic condition that affects the entire skin of a person. Infections, blisters, and burns can be other causes of lighter skin regions.
Pigmentation disorder types
Linea nigra (from the Latin “black line”) is a dark vertical line that appears in the abdomen in approximately 25% of all pregnancies. The brownish ray is usually about one centimeter wide. The line runs vertically along the midline of the abdomen from the pubis to the navel, but can also go from the pubis to the upper abdomen. Linea nigra occurs when the melanocyte-stimulating hormone produced by the placenta increases, which also causes melasma and darkened nipples.
Light-skinned women show this phenomenon less frequently than women with darker pigmentation. Linea nigra usually disappears a few months after delivery.
Melasma, also known as the mask of pregnancy, is a tan or dark coloration of the skin. Although it can affect anyone, melasma is particularly common in women, especially pregnant women and those who take oral or patch contraceptives or hormone replacement therapy (HRT) medications.
Addison’s disease is a long-term endocrine disorder in which the adrenal glands do not produce enough hormones.
They usually appear slowly and may include abdominal pain, weakness, and weight loss. The darkening of the skin can also occur. Under certain circumstances, an adrenal crisis may occur with low blood pressure, vomiting, low back pain and loss of consciousness. An adrenal crisis can be triggered by stress, such as an injury, surgery or infection.
Albinism, a hereditary disorder whose main characteristic is the total or partial absence of pigment in the skin, hair, and eyes. It is associated with a series of vision defects, such as photophobia, nystagmus, and amblyopia. The scarce pigmentation in the skin increases the susceptibility to sunburn and skin cancers.
Pityriasis alba is a common condition of the skin, it is present mainly in children and is generally seen as patches, with fine and pale scales on the face. It is self-limiting and usually only requires the use of moisturizing creams.
The disease takes its name for the fine squamous appearance initially present (pityriasis) and the pallor of the patches that develop (while “alba” is in white Latin, the patches in this condition are not totally depigmented).
Tinea versicolor is a disease that occurs as a rash on the trunk and extremities. In most cases, tinea versicolor is caused by the fungus Malassezia globosa, although Malassezia furfur is responsible for a small number of cases. These yeasts are normally found in human skin and become problematic only under certain circumstances, such as a warm and humid environment, although the exact conditions that cause the onset of the disease process are not well understood.