What is Acanthosis Nigricans?
Acanthosis nigricans is a condition that causes the skin to become dark and velvety in texture, often in areas where the skin folds. These could be the back of your neck, underarms, or your groin area. The borders of this darkened skin aren’t usually clear, and the skin might even become thicker. Most often, this condition is linked to diabetes or insulin resistance. However, in rare cases, it could indicate the presence of an internal cancer. Acanthosis nigricans can also be a symptom of hormonal disorders, or it could appear as a side effect of certain medications such as systemic glucocorticoids and oral contraceptives.
What Causes Acanthosis Nigricans?
- One primary factor is when there’s an increase in insulin in the body. Insulin can trigger growth factors in skin cells, making them grow more. This happens especially when there’s too much insulin, which could lead to the growth of skin and connective tissue cells.
- Genetic variants, where there’s a problem with certain growth factors, can also contribute to this condition.
- Increased growth factor related to cancer could be the reason behind acanthosis nigricans associated with cancer. This type of growth factor influences skin tissue growth.
There’re also different types of acanthosis nigricans:
- Familial acanthosis nigricans: This starts at birth or during childhood because of a mutation in a certain growth factor receptor gene and it’s passed down through families.
- Acanthosis nigricans often happens in people who are overweight. It’s most common in adults, but it can happen at any age. It’s also linked with insulin resistance. Treating obesity by dieting, losing weight, or taking medication can help erase the signs of the condition.
- Some medications can cause acanthosis nigricans, including certain acids, hormones, contraceptive pills, and insulin. Once a person stops taking these medications, the condition typically clears up.
- Acanthosis nigricans can develop slowly due to problems with the endocrine system (which regulates hormones). This form of the condition often occurs in people who are overweight, have uncontrolled diabetes, or suffer from diseases that result in insulin resistance. It’s also common in females with certain medical conditions like ovarian syndrome, sometimes seen in those with specific hormone imbalances.
- There’s a form of acanthosis nigricans, which only affects the elbows, knees, knuckles, and tops of the feet. This type primarily occurs in individuals with dark skin.
- Malignant acanthosis nigricans syndrome is linked with various cancers like those of the gastrointestinal tract, prostate, breast, ovary, and rarely, lung or lymphoma. It could show up before, during, or after the appearance of cancer and is usually accompanied by skin tags and keratoses (skin growths).
- Autoimmune acanthosis nigricans is linked with autoimmune disorders, which are diseases in which the body’s immune system mistakenly attacks its cells.
- Unilateral acanthosis nigricans is a rare inherited form that shows up on one side of the body. The signs can show up in infancy, childhood, or adulthood.
Risk Factors and Frequency for Acanthosis Nigricans
Acanthosis nigricans is a condition that usually affects people under the age of 40. It is often associated with conditions such as obesity, underactive thyroid (hypothyroidism), growth hormone disorder (acromegaly), polycystic ovary disease, insulin-resistant diabetes, and Cushing and Addison diseases. It’s also related to some rare diseases like pinealoma, a particular type of Cushing disease, ovarian hyperthecosis, stromal luteoma, ovarian dermoid cysts, Prader-Willi syndrome, leprechaunism, lipoatrophic diabetes, pineal hyperplasia syndrome, and Alstrom syndrome.
In the United States, acanthosis nigricans is more common among Native Americans, African Americans, and Hispanics compared to people of White or Asian origin.
Signs and Symptoms of Acanthosis Nigricans
Acanthosis nigricans is a skin condition usually marked by an area of skin that becomes darker and thicker, often accompanied by itching. The skin changes may involve dark, velvety patches or spots that can evolve into noticeable plaques. An interesting aspect of a form of this condition, called malignant acanthosis nigricans, is its relationship with cancer.
In about one-third of patients, skin changes occur before the cancer signs. In another one-third, skin lesions emerge simultaneously with the cancer diagnosis. For the rest of the patients, skin symptoms appear only after the detection of cancer. These skin alterations sometimes appear suddenly and can be associated with intense itching.
- Dark, thickened skin
- Velvety, hyperpigmented spots or patches
- Plaques which can be felt by touch
- Skin changes occurring before, with, or after cancer signs
- Potential for sudden appearance
- Possibly involves intense itching
These skin changes typically occur in body areas with skin folds, such as the groin, armpit, or back of the neck. In children, the back of the neck is the most common area. Interestingly, acanthosis nigricans can sometimes be seen on the moist linings of the nose, mouth, esophagus, larynx, and even on a woman’s nipple. There have also been rare reports of acanthosis nigricans in the eye’s conjunctiva.
Some patients may also develop skin tags in the same area. Changes to the nails, such as thickening (hyperkeratosis) and white spots or streaks (leukonychia), may also be observed. However, it’s important to note that it’s not possible to tell the difference between benign (non-cancer-related) and malignant acanthosis nigricans simply by looking at the lesions.
Testing for Acanthosis Nigricans
Acanthosis nigricans is primarily determined by physical examination and affirmed by a skin biopsy. Additional measures like blood tests, using an endoscope for internal visualization, or X-ray scans might be needed to exclude other health issues like diabetes or cancer. If a skin biopsy is undertaken, changes like thickening of the skin (hyperkeratosis), the increase of white blood cells (leukocyte infiltration), folding of the outermost layer of the skin (epidermal folding), and growth in the skin’s pigment-producing cells (melanocyte proliferation) might be noticed.
The main goal of these checks is to make sure it is not caused by cancer. As most instances of this condition are linked to obesity and/or resistance to insulin – a hormone that controls blood sugar levels, a screening test for diabetes and a specific test to measure the amount of sugar attached to hemoglobin in red blood cells (glycosylated hemoglobin test) are recommended.
Treatment Options for Acanthosis Nigricans
Acanthosis nigricans, a skin condition, can’t be directly cured. However, it may fade over time if its root cause, such as insulin resistance, is treated. Lifestyle changes like regular exercise and a balanced diet to control blood sugar levels can help diminish symptoms. Lighter skin creams can also help in less severe cases. If the condition is related to a tumor, it may disappear if the tumor is successfully removed.
The main aim of the treatment is to handle the underlying condition causing acanthosis nigricans. More often, treatment is performed for aesthetic purposes instead of health needs. For some people, weight loss and re-balancing insulin levels can reduce the impact of thickened skin patches. Medications such as metformin and rosiglitazone, which help make the body more responsive to insulin, can be used to treat acanthosis nigricans if it is linked to insulin resistance.
It is recommended to stop all triggering substances and medications. Efforts should also be made to lower cholesterol levels. Incorporating dietary fish and niacin into meals has been suggested as helpful.
Dermatologists might recommend skin medications (keratolytics), such as topical retinoids, and a substance called podophyllin, to help treat the condition. Topical vitamin D creams, like calcipotriol, work by slowing the growth of skin cells and can help improve the condition of the skin patches. Yet, the effectiveness of these treatments can vary. Other treatments, such as metformin, etretinate, and a drug called octreotide, have been found useful for some people.
Melatonin, a hormone that regulates sleep, can also ameliorate skin symptoms in obese patients with acanthosis nigricans by reducing inflammation and boosting insulin sensitivity.
Various cosmetic procedures such as laser treatment, skin polishing (dermabrasion), and chemical peels have been tried for aesthetic improvement. For malignant lesions, surgical removal is the primary treatment.
What else can Acanthosis Nigricans be?
- Seborrhea (A skin condition that causes flaky, itchy, red skin)
- Tinea (A fungal infection of the skin, also known as ringworm)
- Erythrasma (A type of skin infection caused by bacteria)
- Candidiasis (A fungal infection, also known as yeast infection)
- Pellagra (A disease caused by a deficiency of the nutrient niacin/vitamin B3)
- Ichthyosis (A group of skin disorders causing dry, thickened, scaly skin)
- Linear epidermal nevus (A type of birthmark in the skin’s outermost layer)
- Granular parakeratosis (A rare skin condition characterized by rough, scaly patches)
- Cutaneous hyperpigmentation related to Addison disease (A symptom of Addison disease that makes the skin appear darker than normal)
What to expect with Acanthosis Nigricans
People with a less severe type of acanthosis nigricans—a skin condition—generally have little to no skin complications. They also have a good chance of getting better, especially with treatment. However, complications can arise if the person is dealing with underlying conditions such as diabetes and insulin resistance.
On the other hand, people with a severe, or malignant, type of acanthosis nigricans have a less favorable outlook. This is because, typically, by the time this condition is diagnosed, the skin disorder has already advanced significantly.
Possible Complications When Diagnosed with Acanthosis Nigricans
What complications arise from acanthosis nigricans depends on what’s causing it. In most instances, it is due to insulin resistance. However, in some cases, it can be linked with more severe issues, such as cancer.
Preventing Acanthosis Nigricans
If you notice an unusual darkening of your skin, this could be more than just a skin condition and it’s recommended to get it checked out, especially if you are middle-aged or older. It’s important to stay in communication with your doctor about any changes in your skin color. This darkening, known as hyperpigmentation, could be due to a condition called acanthosis nigricans. It can get better, and might even go away completely, with the right treatment for your skin or for an underlying condition that might be causing it.
You should educate yourself about the risk factors and signs of acanthosis nigricans, as it can sometimes indicate a more serious health condition. Some people with acanthosis nigricans might also experience feelings of depression or low self-esteem. Identifying and treating these emotional health issues early is important for a full and comprehensive recovery.
