What is darkened skin?
Darkened skin, or hyperpigmentation, is the appearance of patches of skin that become darker than the surrounding area. Hyperpigmentation can also diffusely involve the total skin surface of the body. The change in color happens when there is overproduction of melanin, the pigment normally found in the skin, forming deposits that darken the skin color. Darkened skin can develop in people of all races. Melasma is increased skin pigmentation that usually occurs on sun-exposed surfaces of darkly complected individuals.
Commonly, darkened skin appears as fairly small spots, called “age spots” or lentigines, which can be caused by sun damage acquired over a long period of time. In fact, sun exposure is one of the most common causes of darkened skin. Energy from the ultraviolet rays of the sun is absorbed by melanin as a normal way to protect the skin from overexposure. This can also darken areas that already have hyperpigmentation.
Sometimes darkened skin occurs as a result of a hormonal change (for example, during pregnancy or with the use of birth control pills) or as a symptom of a particular disorder, such as café au lait macules, which are light or dark brown patches of skin present from birth, or Addison’s disease, which is characterized by deceased production of hormones by the adrenal glands. Darkened skin can also result from a combination of sun exposure and an allergic reaction, usually to a specific plant or chemical.
In some cases, darkened skin can be temporary, such as during pregnancy or while using birth control pills. Some, but not all, forms of hyperpigmentation can be effectively lightened with medications or lasers; other forms can fade with a change in medication or a change in hormone levels.
Darkened skin is not a symptom of a life-threatening condition. However, in some cases it can be a symptom of another disorder that will need treatment. Seek prompt medical care if you have darkened skin and are also experiencing fatigue, loss of appetite, or sudden depression; if the darkened areas are also occurring in your mouth or other mucus membranes; or if you are experiencing diarrhea or constipation.
If your darkened skin is persistent or causes you concern, seek prompt medical care.
What other symptoms might occur with darkened skin?
Darkened skin may accompany other symptoms, which vary depending on the underlying disease, disorder or condition. Conditions that frequently affect the skin may also involve other body systems.
Skin symptoms that may occur along with darkened skin
Darkened skin may accompany other symptoms affecting the skin including:
- Burning feeling (in cases of reactions to chemical exposure)
- Flaky skin, peeling (occasionally)
- Itchy skin
- Redness, warmth or swelling
Other symptoms that may occur along with darkened skin
Darkened skin may accompany symptoms related to other body systems including:
- Depression
- Diarrhea
- Glucose intolerance
- Joint pain
- Little interest in sex
- Loss of appetite
- Missed menstrual periods
- Pain in the upper right abdomen
Symptoms that might indicate a serious condition
In some cases, darkened skin may occur with other symptoms that might indicate a serious condition which should be evaluated by a healthcare provider. Seek prompt medical care if you have darkened skin along with other serious symptoms including:
- Constipation
- Depression or irritability and mood changes
- Diarrhea
- Excessive urination and thirst
- Fatigue
- Fluctuations in blood pressure
- Joint pain
- Loss of appetite or unexplained weight loss with increased appetite
- Missed menstrual periods and little interest in sex
- Pain in the upper right abdomen
What causes darkened skin?
Some of the most common forms of darkened skin are caused by sun damage, specifically from the ultraviolet rays of the sun. Darkening of the skin can also result from a hormonal change, a congenital or hormonal disorder (as happens in Addison’s Disease), or a combination of sun exposure and allergic reaction (usually to a specific plant or chemical).
Genetic causes of darkened skin
Darkened skin may be caused by congenital or genetic conditions including:
- Incontinenta pigmenti
- Neurofibromatosis (café au lait macules, which are light or dark brown patches of skin present from birth)
- Xeroderma pigmentosum (a genetic disorder of DNA repair)
Hormonal causes of darkened skin
Darkened skin can also be caused by hormonal changes in the body including:
- Addison’s disease (deceased production of hormones by the adrenal glands)
- Cushing’s disease (excessive circulating levels of corticosteroids)
- Hyperthyroidism (overactive thyroid)
- Pregnancy
- Oral contraceptives
Environmental causes of darkened skin
Darkened skin can also be caused by exposure to external factors in the environment including:
- Sunlight
- Toxic chemicals (arsenic)
Other causes of darkened skin
Other causes of darkened skin include:
- Diabetic dermopathy (light brown, scaly patches due to diabetes-related changes in blood vessels)
- Hemochromatosis
- Tinea versicolor (fungal skin infection, malassezia furfur)
Serious or life-threatening causes of darkened skin
In some cases, darkened skin may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:
- Addison’s disease (deceased production of hormones by the adrenal glands)
- Hemochromatosis (a disorder characterized by excess iron in the body)
Questions for diagnosing the cause of darkened skin
To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your darkened skin such as:
- How long have you had this area of darkened skin?
- Do you have darkened skin on any other parts of your body?
- Have you had any redness, scaling or itching?
- Do you feel warmth near the site?
- Do you have any allergies?
- Have you been exposed to any harsh chemicals?
- What medications are you taking?
- Do you have any other symptoms?
Darkened skin, or hyperpigmentation, is not typically a symptom of a life-threatening condition, nor does it, on its own, lead to complications. However, certain disorders associated with hyperpigmentation can lead to complications that are life threatening. Because darkened skin can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications from a variety of these disorders including:
- Diabetic neuropathy (nerve damage due to high blood sugar levels associated with diabetes)
- Diabetic retinopathy, cataracts, and blindness (serious vision complications of diabetes)
- Hidden (occult) cancer (skin changes can signal occult malignancy)
- High blood pressure (hypertension)
- Kidney disease, including any type of kidney problem such as kidney stones, kidney failure, and kidney anomalies)
- Osteoporosis (thinning and weakening of the bones)
- Thyrotoxic crisis (fever, rapid heart rate, and delirium)
