If you have dark knuckles you may be wondering what it means and what you can do about it. Diabetes is a common cause of dark knuckles, but other medical conditions can also cause this symptom.
In this article, we will explore the link between dark knuckles and diabetes and what treatment options are available for you.
We will also discuss ways to help prevent dark knuckles in the future and list any other health conditions that can cause them.
What are the symptoms of diabetes?
The most common symptom of uncontrolled diabetes is high blood sugar levels, also called blood glucose levels, caused by a lack of the hormone insulin or due to your cells developing insulin resistance. Other common symptoms include:
- Frequent urination
- Increased thirst
- Increased hunger
- Unexplained weight loss
- Irritability and mood swings
- An increased risk of infections
- Blurry vision
- Wounds or sores that take longer than normal to heal
If you have any of the above symptoms, please see your doctor or health care provider for medical care and a diagnosis.
Does diabetes cause dark knuckles?
Dark knuckles can be a symptom of diabetes and prediabetes but it is not always indicative of either. If you have prediabetes there will likely be no signs or symptoms of it and the only way to know for sure is through tests and a diagnosis by your doctor.
However, if the dark knuckles are a symptom of prediabetes you can help reverse the condition by making lifestyle changes such as eating a healthy diet and exercising regularly.
Why diabetes and prediabetes cause dark knuckles is unknown although there is a theory that too much insulin can affect your skin cell growth.
If you have type 2 diabetes you are also at a higher risk of developing the skin condition acanthosis nigricans, which develops into dark patches of skin in certain areas, typically on the back of the neck, groin, or underarms.
The skin may appear as dark velvety patches and also have a foul smell, too.
Other risk factors for acanthosis nigricans besides insulin resistance include obesity, being African American, Native American, or Latino, or having a family history of the condition.
If you have acanthosis nigricans you may have diabetes although you can have the condition without being diabetic.
What other medical conditions can cause dark knuckles?
Diabetes, prediabetes, and acanthosis nigricans are not the only medical conditions that can cause dark knuckles.
Other medical conditions that can cause dark knuckles include the following:
Addison’s disease is a rare disorder that occurs when the adrenal glands do not produce enough of the hormones cortisol and aldosterone.
The most common symptom of Addison’s disease is a darkening of the skin called hyperpigmentation which can occur anywhere on your body but typically starts in places where there are skin creases like on your knuckles or near scars.
Other autoimmune disorders besides type 1 diabetes
Autoimmune disorders occur when your immune system attacks healthy cells in your body by mistake. There are a variety of different autoimmune disorders that can cause dark knuckles, such as lupus, celiac disease, Sjögren’s syndrome, and vitiligo.
Polycystic ovary syndrome
Polycystic ovary syndrome (PCOS) is a hormonal disorder that affects women of childbearing age. It occurs when the ovaries produce too many male hormones in women.
One symptom of PCOS is darkening of the skin, typically on the neck, chest, underarms, or where there are skin folds such as the knuckles.
If you have a vitamin B-12 deficiency your body may react by darkening your knuckles.
A vitamin B-12 deficiency can be caused by a variety of things, including not getting enough vitamin B-12 in your diet, pernicious anemia (an autoimmune disorder that affects your body’s ability to absorb vitamin B-12), alcohol abuse, or certain medications.
The darkened knuckles will likely go away after you correct the deficiency.
Dermatomyositis is a rare autoimmune disorder that causes muscle weakness and a skin rash. It typically affects children but can occur in adults as well.
The skin rash associated with dermatomyositis can cause darkening of the skin, particularly on the face, knuckles, elbows, knees, or chest. The rash will be blue/purple or red in color.
Side effects of medications
Some medications can cause darkening of the skin as a side effect.
These include certain birth control pills, growth hormone therapy, estrogen therapies, and insulin among others. If you are taking any medication and develop dark knuckles as a side effect you need to speak to your doctor about switching to an alternative drug.
Scleroderma, also called systemic sclerosis, is a rare autoimmune disorder that causes the skin to harden and tighten due to excess collagen.
Scleroderma can cause skin darkening on the hands and fingers as well as Raynaud’s phenomenon which is when the blood vessels in your fingers and toes constrict in response to cold weather or stress. In extreme cases, scleroderma can cause the tips of your fingers to turn blue or purple due to poor blood flow (called digital ischemia).
What are the treatment options for dark knuckles?
The treatment for dark knuckles will depend on the underlying cause.
If your dark knuckles are due to diabetes, then treating diabetes will usually also treat the dark knuckles which may involve making lifestyle changes such as eating a healthy diet and exercising regularly, and taking medication to control blood sugar levels.
Another medical condition, such as an autoimmune disorder, may also be the cause and treatment will focus on the underlying condition which may also involve taking medication or making lifestyle changes.
If dark knuckles are a side effect of medication, then speak to your doctor about switching to a different medication. In some cases, dark knuckles may not require treatment and may go away on their own.
If you treat the underlying cause of dark knuckles and they do not go away, there are some home remedies you can try to help lighten the skin. These include:
- Applying lemon juice on a cotton swab to the area daily
- Make a paste with water and baking soda and apply it to the affected knuckles for 10-20 minutes daily
- Use a moisturizing cream every day to help prevent discoloration
- Use sunscreen whenever you are in the sun to avoid darkening your skin even more
Other methods have been shown to help with skin lightening in some studies although more research is needed to come to any firm conclusions. These include:
- Drinking certain types of tea that have epigallocatechin gallate, a type of catechin, has been shown in one study to help lighten the skin
- Vitamin C since it is an antioxidant that has been shown to help keep your skin healthy
- Licorice extract
- Kojic acid
- Aloe leaf extract
- Ellagic acid
- Lignin peroxidase
Please read all the ingredients of anything you buy to ensure they contain these ingredients and always consult with your doctor before starting any new treatments.
There are also medications that can help lighten dark knuckles.
These include keratolytics (including retinoids that increase the production of collagen), topical vitamin D solutions, and melatonin.
Some of these are available as prescription medications while others can be found as over-the-counter medications and you need to speak to your doctor or dermatologist before starting any new treatment.
Are there any ways to prevent dark knuckles?
There are a few ways you can prevent dark knuckles from getting worse or developing in the first place. Whenever you are in the sun you need to wear sunscreen to avoid darkening your skin even more.
If you have diabetes, make sure to keep your blood sugar levels under control to help prevent dark knuckles by eating a healthy diet, exercising regularly, maintaining healthy body weight, and taking any medications as prescribed by your doctor.
Finally, if medication for another health issue is causing darkened skin you need to consult with your doctor to determine if there is an alternative one without these side effects. Depending on the underlying cause, there may not be a way to prevent dark knuckles.
Dark knuckles can be caused by several different factors including diabetes.
Treatment for them will focus on treating the underlying medical issues although, in some cases, the darkening of knuckles may not require treatment and may go away on their own.
There are also home remedies and prescription medications that can help lighten dark knuckles and you need to talk to your doctor before starting any new treatments.
Preventing dark knuckles is not always possible but you can try to avoid them by taking precautions such as wearing sunscreen, switching any medications that may be causing it, and keeping your blood sugar levels under control if you have diabetes.
If you have any more questions regarding dark knuckles or diabetes please talk to your doctor or dermatologist.
References and sources:
American Academy of Dermatology Association
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Diabetic.org is devoted to producing expert and accurate articles and information for our readers by hiring experts, journalists, medical professionals, and our growing Diabetic.org community. We encourage you to read more about our content, editing, and fact checking methods here. This was fact checked by Jacqueline Hensler and medically reviewed by Dr. Angel Rivera.
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