Hyperpigmentation: what are the causes of dark spots on the skin?

Hyperpigmentation (increased pigmentation of the skin) is characterized by increased production of a dye by the cells of the skin. This dye is of two types. The first is melanin. It is produced by special skin cells and the dye is brown-black in colour.

Hyperpigmentation = areas of skin, smaller or larger, with increased pigment = darker spots.
You may often be interested in: post-inflammatory hyperpigmentation, dark skin on face, hands or feet, age spots.

It occurs, for example, when sunbathing.

Freckles, or ephelides, are also a sign of excess melanin. These are actually sharply defined spots up to a few millimetres in size.

Larger spots are melasma, also known as chloasma uterinum, which is caused by hormonal influences, mostly during pregnancy. They are most often found on the temples and face. They are also sharply defined and their colour is yellowish-brown or yellowish.

Poikilodermia of Civatte occurs in middle-aged women, mainly on the neck.

Similarly, sun spots are also referred to by the inappropriate name of age spots. They are usually formed after the age of 40 due to prolonged exposure to UV rays. They are small, darker but flat hyperpigmentations.

Melanin hyperpigmentation is also present, for example, in Peutz-Jehens syndrome or Bloch-Sulzberg syndrome, which are relatively rare diseases.

The second type of dye is hemosiderin, which is rusty brown in colour. This dye has its origin in the blood dye haemoglobin. Sometimes the hyperpigmentation is of only one type, sometimes it is mixed.

Increased pigmentation with hemosiderin is common in various vascular diseases, for example, on the ankles of the legs in chronic venous insufficiency disease, or in diseases of increased bleeding with manifestations on the skin.

Secondary hyperpigmentation

It occurs after other diseases, skin inflammations, but also after trauma and mechanical damage to the skin. It can also be caused by chemicals, but also by physical exposure.

Postinflammatory hyperpigmentation.

It is common in psoriasis, eczema or atopic eczema.

In various rashes, in the healing of psoriasis. Also in the case of some diseases of the endocrine system, it is possible to observe a greater pigmentation of the skin as one of the symptoms. It appears, for example, in Cushing's syndrome.

This disease is characterised by increased production of cortisol. Cortisol is a hormone that is produced in the adrenal glands. In this case, hyperpigmentation occurs in women who have increased growth of pigmented hairs, specifically on the face, chin and upper lip, as one of the symptoms of the disease.

Excessive deposition of iron in the tissues in the form of one of the pigment dyes is also a manifestation of haemochromatosis, a disease that causes haemosiderin, a dye originally found in haemoglobin, to be deposited in cells and tissues.

In addition, liver enlargement is present in this disease. Often people who suffer from this disease also have diabetes. Some people also have hyperpigmentation of the conjunctivae.

Melanoma, which is also referred to as skin cancer, is also a cancer that originates in melanocytes - the skin cells that produce this type of skin pigment.

This skin disease is also caused by the sun and excessive sun exposure. In recent years, the number of people with melanoma has increased rapidly. This is mainly due to inadequate sun protection, either by excessive sun exposure or by not using sunscreen. The treatment in this case also consists of surgical removal.

Another skin disease in which increased pigmentation of the skin is characteristic is basal cell carcinoma. This is a malignant skin tumour that mainly affects people in older age, over 70 years.

This tumour appears on skin that may otherwise be healthy. In most cases, it is on the face. However, the tumour is relatively easy to treat because it does not spread to other parts of the body. It is usually treated by surgical removal.

Spots on the skin are also caused by diseases or exogenous agents such as:

• Addison's disease.
• pituitary hyperfunction
• melanoderma
• neurofiromatosis
• herpes zoster
• transient diffuse hyperpigmentation
• melanosis in smokers
• Nelson syndrome (rare pituitary adenoma)
• Cockayne syndrome
• chronic venous insufficiency of the lower extremities
• varicose veins or varicose veins of the lower limbs
• after medication (cytostatics)
• after burns
• liver disease
• diabetes
• sclerosing cholangitis