Dark Knuckles: Causes And Treatment

Written by Arshiya Syeda

Are you bothered by the dark patches on your knuckles? Don’t worry, they are quite common, especially in people with darker skin tones. These patches are not age-specific, and anyone can develop this harmless condition.

But sometimes, dark knuckles can be an indicator of an underlying medical condition. They may form due to a metabolic disorder such as diabetes or as a side effect of certain medications.

Keep reading to learn more about the possible causes and treatment options for your darkening knuckles.

What Causes Dark Knuckles?

Dark knuckles can occur without any specific reason and may also be a symptom of certain medical conditions. Following are the common causes of dark knuckles:

1. Acanthosis Nigricans (AN)

Acanthosis nigricans (AN) is a skin condition that causes dark patches and velvety textures on your skin (1). It can affect the skin on folds and joints, including your knuckles. Although it is not an infection, it may cause itchiness and odor.

AN is more prevalent in people of Native American, African, and Hispanic backgrounds. Having a family history of AN and obesity can increase your risk of developing this condition.

Experts believe that the mutation of the gene responsible for the fibroblast growth factors may lead to AN (2). It can also be a warning sign for other conditions, including diabetes, hormonal imbalances, PCOS, or cancer. Additionally, it may be a side effect of contraceptives or cholesterol medications.

2. Diabetes

Experts believe there is a relationship between dark knuckles and diabetes. Darkening of the skin may signal the onset of diabetes. Prediabetes is a stage where the blood sugar levels are higher than the normal limit (3). Skin darkening is said to be, in most cases, the only warning sign. This is because altered levels of insulin in your body can result in hyperpigmented patches of skin, including darkening of knuckles.

Recognizing this sign of prediabetes can aid in early intervention and management of diabetes.

Skin hyperpigmentation also reflects poor management of diabetes (4). In such a scenario, you will most likely require a change in your treatment approach.

3. Dermatomyositis

The dark spots on your knuckles may be the result of dermatomyositis. It is an inflammatory disorder affecting the muscles and skin. This chronic condition can cause skin rashes on the knuckles, face, chest, knees, and elbows. The color of these rashes varies from bluish-purple to red.

Although dermatomyositis is not curable, if detected early, the symptoms are manageable with proper treatment.

4. Polycystic Ovary Syndrome (PCOS)

Polycystic ovarian syndrome (PCOS) is caused by an imbalance of hormones in women. It is more prevalent during the child-bearing age. One of the symptoms of PCOS is dark patches on the skin, often along the creases and joint folds (5).

5. Addison’s Disease

Addison’s disease is an uncommon disorder. It occurs when your body produces reduced levels of the steroid hormones cortisol and aldosterone.

Cortisol is vital when the body is under stress, and its low levels can be life-threatening. Symptoms tend to include fatigue, nausea, darkening of the skin, and dizziness. Skin darkening at the knuckles can be among the initial symptoms of Addison’s disease.

6. Scleroderma

Scleroderma is an autoimmune disorder in which your body attacks your tissues and overproduces collagen. Collagen hardens and tightens the skin and other connective tissues. Redness of the skin on your hands and knuckles are some of the symptoms of scleroderma (6).

7. Vitamin B12 Deficiency

Dark spots on the knuckles can be a sign of a vitamin B12 deficiency (7). Treating this vitamin deficiency with adequate dietary supplements and modifications can get rid of the darkening.

​ 8. Drug Reactions

Darkened knuckles can also be a side effect of certain medications. These include:

  • Oral contraceptives
  • Hormonal replacement therapy
  • Glucocorticoids
  • Anticoagulants
  • Antibiotics, like tetracyclines
  • Niacin and nicotinic acid
  • Insulin in injectable form

If you are taking any of these medications and develop darkened knuckles, consult your doctor. A change in the prescription may help get rid of the darkening skin.

If your dark knuckles have a sudden onset, they are most likely due to an underlying cause. Addressing the underlying cause is of utmost importance when it comes to treating dark knuckles. With appropriate treatment, in most cases, the skin darkening disappears.

Check out some treatment methods, including DIY home remedies, below.

How To Lighten Severely Dark Knuckles

Tempting though it might be, avoid scrubbing or bleaching your knuckles. Scrubbing can prove counter-productive by removing the protective layer of superficial skin and increasing pigmentation. And, over-the-counter bleaches contain high concentrations of strong acids that can worsen skin darkening.

Instead, try the following ways to lighten your dark knuckles:

1. Medical Treatment For Dark Knuckles

When the cause of dark patches on the knuckles is an underlying medical condition, the first line of treatment involves medications or lifestyle changes per the diagnosis.

For metabolic disorders like PCOS or diabetes, weight control, diet modifications, and correct treatment can relieve darkened knuckles.

For a vitamin B12 deficiency, dietary supplements can give you immediate results.

In conditions such as Addison’s disease, hormone replacement therapy may be necessary for getting rid of hyperpigmentation.

2. Home Remedies For Dark Knuckles

The following home remedies may help you lighten the skin tone on your knuckles. They will, however, not completely clear your skin unless you address the root cause.

  • Turmeric

Turmeric contains curcumin, an active compound known for its skin-lightening property. Curcumin disrupts melanin synthesis, thus minimizing skin darkening (8). You can mix a small quantity of powdered turmeric in a bit of water and apply the paste to your knuckles for some time before washing it off.

  • Green Tea

You can also try green tea to get rid of dark knuckles. Tyrosinase enzyme is essential for synthesizing melanin in your body. Green tea contains epigallocatechin gallate which inhibits tyrosinase. Therefore, regular topical use of green tea can help lighten dark knuckles (8).

You can make a green tea decoction by steeping a green teabag or some green tea leaves in warm water. Apply this decoction on the darkened skin. Alternatively, you can apply a mix of green tea with milk and rose water to your knuckles. Do it for a few days for substantial results.

  • Curd

While there is limited research on this claim, curd is said to possess a potential skin-lightening effect due to its high lactic acid content. It is claimed to exfoliate the skin, reduce inflammation, and also stimulate skin growth.

You can apply curd directly to your knuckles and leave it to dry for about 20 minutes. Then, wash it off with warm water.

  • Vitamin C

Vitamin C is a potent antioxidant that can prove effective against several skin problems such as hyperpigmentation. Studies show that vitamin C impedes melanin production (9). Thus, it may help lighten dark knuckles.

​ 3. Over-The-Counter Remedies For Dark Knuckles

You can also opt for over-the-counter (OTC) products for your dark knuckles. These products are available in the form of creams, serums, moisturizers, and gels.

Note that these drugs work differently for different people, so consult your doctor before using these medications.

Experts recommend OTC products with the following ingredients for lightening dark knuckles (8).

  • Kojic acid
  • Niacinamide
  • Ellagic acid
  • 2% Hydroquinone
  • Azelaic acid
  • Glycolic acid
  • Retinoids (retinol, tretinoin, adapalene gel, or tazarotene)

If you have dark knuckles on your hands, these treatment options can help you lighten them. But, is there any way to prevent these patches from appearing in the first place? Continue reading to find out.

How To Prevent Dark Knuckles

When not the symptom of a more serious condition, dark, dry knuckles are easy to prevent. Moisturizing your hands and applying sunscreen to them regularly can reduce the wear and tear of the skin on your knuckles. Such skin is less likely to develop dark spots.

​ When Should You Consult A Doctor For Darkened Knuckles?

If the skin on your knuckles is getting darker without any reason, or if the color change occurs suddenly, consult a healthcare professional. Also, if you have any other symptoms, discuss them with your doctor. Darkening skin can be a sign of an underlying condition requiring medical attention.


Dark knuckles typically are not a concern and require no specific treatment. In some cases, they can be an early sign of a medical condition. With a proper diagnosis, you can start appropriate treatment for skin darkening. Most cases of dark spots on knuckles show marked improvement with treatments.

If the darkening does not have a medical cause, you can try some home remedies or OTC products to lighten the dark knuckles.


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