Specific types of nail discoloration can be signs of underlying conditions that should be identified and treated by a medical professional.
If your toenails appear to be blue, it could be an indication of:
- subungual hematoma
- cold weather
- Raynaud’s phenomenon
- drug interaction
- blue mole
- Wilson’s disease
Keep reading to learn more about these possible conditions, and their treatment.
Subungual hematoma is bruising under the nail bed, which can have a bluish-purple color. When you experience trauma to your toe, such as stubbing it or dropping something heavy on it, small blood vessels can bleed underneath the nail. This can result in discoloration.
According to the American Osteopathic College of Dermatology (AOCD), you can typically take care of a subungual hematoma with self-care. Treatment options include:
- over-the-counter (OTC) pain medication
- ice (to reduce swelling)
In some cases, your doctor may recommend that they make a small hole in the nail to drain pooled blood and relieve pressure.
When the temperature gets cold, your blood vessels constrict, making it difficult for enough oxygen-rich blood to reach the skin under your nails. This can cause your nails to appear blue. But it’s actually the skin underneath your nails that’s turning blue.
Warm foot protection can prevent this from happening to your toes.
Too little oxygen in the blood or poor circulation can cause a condition called cyanosis. It gives the appearance of a blue color of your skin, including the skin under your nails. The lips, fingers, and toes may appear blue.
Restricted blood flow can cause discoloration under the nail. Make an appointment with a doctor, especially if you have other symptoms, such as shortness of breath, dizziness, or numbness in the affected area.
Treatment of cyanosis typically starts with addressing the underlying causes for the restricted blood flow. Your doctor may also recommend medications to relax your blood vessels, such as anti-hypertension medications and antidepressants.
People experiencing Raynaud’s phenomenon have restricted or interrupted blow flow to the fingers, toes, ears, or nose. This happens when blood vessels in the hands or feet are constricted. Episodes of constriction are called vasospasms.
Often triggered by cold temperatures or stress, vasospasms can have symptoms that may include numbness in your toes or fingers, and color changes to the skin. Typically, the skin turns white and then blue.
Raynaud’s phenomenon is often treated with medication to dilate (widen) blood vessels, including:
- vasodilators, such as nitroglycerin cream, losartan (Cozaar), and fluoxetine (Prozac)
- calcium channel blockers, such as amlodipine (Norvasc) and nifedipine (Procardia)
According to BreastCancer.org, you may notice some changes in the color of your nails during treatment for breast cancer. Your nails may look bruised, turning a blue color. They may also appear black, brown, or green.
Breast cancer medication that can cause nail changes include:
- daunorubicin (Cerubidine)
- docetaxel (Taxotere)
- doxorubicin (Adriamycin)
- ixabepilone (Ixempra)
- mitoxantrone (Novantrone)
A blue spot under your toenail for no obvious reason could be a blue nevus.
In rare cases, according to the American Osteopathic College of Dermatology (AOCD), a type of blue mole known as a cellular blue nevus can become a malignant cellular blue nevus (MCBN) and should be biopsied.
If you have an MCBN, your doctor will most likely recommend surgical removal.
Although rare, argyria (silver toxicity) is a result of prolonged or high exposure to silver. One of the symptoms of this condition is a bluish-gray staining of the skin.
Exposure to silver is often traced to:
- occupational exposure (silver mining, photographic processing, electroplating)
- colloidal silver dietary supplements
- medication with silver salts (wound dressing, eye drops, nasal irrigation)
- dental procedures (silver dental fillings)
If you’re diagnosed with argyria, your doctor may first recommend ways to avoid further exposure.
According to a 2015 review article published in the Journal of the European Academy of Dermatology and Venereology, laser treatment may potentially be an effective treatment for argyria.
For some people with Wilson’s disease (hepatolenticular degeneration), the lunula of the nail can turn blue (azure lunula). The lunula is the white, rounded area at the base of your nails.
Wilson’s disease is commonly treated with drugs that help remove copper from tissue. These drugs include trientine hydrochloride or D-penicillamine.
Made up of layers of keratin, your toenails protect the tissues of your toes. Keratin is a hardened protein also found in your skin and hair. A smooth surface and consistent pinkish color usually indicate healthy nails.
If you have blue toenails and the discoloration is not easily explained, for example by trauma, you could have an underlying condition.
These conditions may include argyria, cyanosis, Raynaud’s phenomenon, Wilson’s disease, or blue nevus. If you suspect any of these conditions, see a doctor for a full diagnosis and recommended treatment plan.