Apart from too much exposure to the sun, medical conditions like Addison’s disease, melasma and lupus can cause darkening of the skin.
Skin darkening, commonly referred to as hyperpigmentation is an indication that too much melanin (pigment) is being produced in the skin. Melanin producing cells, also known as melanocytes lie in the lowest layer of the epidermis. When there is excessive production of melanin, it can lead to formation of small dark patches on the skin.
Too much application of cosmetic products or use of antibiotics can cause hyperpigmentation. Other causes are explained below:
Too much exposure to the sun is something that cannot be tolerated by the skin. This can lead to hyperpigmentation in an uneven manner. For instance, the color of outer thighs may appear darker than that of inner thighs. Sitting or traveling in the hot sun for a longer duration causes excessive secretion of melanin in the skin. This happens because the UV rays enter the skin and stimulate melanocytes to produce more melanin, which eventually makes the skin darker.
Addison’s disease can also make the skin abnormally dark. This disease is typically marked by improper functioning of the adrenal glands that are found above the kidneys. The adrenal gland is responsible for producing a number of hormones that help to maintain health. The pituitary gland situated near the brain, controls the adrenal gland. With the malfunctioning of the adrenal gland, the pituitary gland responds by producing corticotropin (a hormone) in excess amounts. This too much production of corticotropin forces the melanocytes to release extra melanin into the skin. No wonder, people with Addison’s disease suffer from dark pigmentation that is visible in the form of brown patches on the skin. Patients may also experience fatigue and a feeling of dizziness.
Hyperpigmentation is also considered to be one of the symptoms of lupus. Surprisingly, in lupus, the invasion is not from any bacteria or viruses but from the immune system itself. It attacks the tissues of the joints and the skin, which gives rise to a rash that makes a butterfly shaped pattern in the affected area. This condition is notorious for causing dark patches on the skin, joint inflammation, fever, mouth sores, and muscle pain.
Hyperpigmentation, can also be due to alkaptonuria, a genetic defect in which the body loses its ability to metabolize certain amino acids. This leads to accumulation of homogentisic acid in the urine, joints and the skin tissues. As a result, the acid buildup not only causes skin discoloration but can also damage the joints as well as increase the risk of kidney stones.
Melasma can also darken the complexion. This is a skin disorder that manifests in the form of dark brown patches on the cheeks, forehead and the chin. Reports suggest that it is commonly diagnosed in women than in men. In fact, melasma occurring in men is relatively uncommon. Hormonal imbalance during pregnancy is many times the main culprit behind causing melasma. Women taking birth control pills or anti-seizure medicines can also suffer from melasma.
Use of skin lightening creams is the conventional treatment to get rid of these dark patches on the superficial skin. Generally, these skin creams that lighten dark pigmentation contain hydroquinone, corticosteroids or tretinoin. As over exposure to sunlight is the most common cause of skin darkening, use of sunscreen lotion is one of the best ways to keep hyperpigmentation at bay. In case the dark patches do not go away with skin cream, consulting a qualified dermatologist is necessary to find out the underlying cause.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.