A black toenail that lasts for years is often due to chronic trauma (like tight shoes), a persistent fungal infection, or pigment changes (melanonychia) from moles or melanin, but it can sometimes signal a serious condition like melanoma, so seeing a doctor for diagnosis is crucial to rule out skin cancer, especially if the spot changes or isn't painful.
In some cases, a black toenail may be caused by a fungal infection, which can darken the nail over time. Less commonly, it could be related to underlying health issues like diabetes, poor circulation, or (very rarely) a form of skin cancer under the nail.
A bruised toenail is caused by bleeding beneath the nail, which can happen after an injury or other trauma to the nailbed (e.g., chronic rubbing within your shoes). If the injury covers a large area of the toe or is painful, medical treatment may be needed to relieve pressure and help prevent permanent nail changes.
Black toenails will typically go away on their own, but it can take several months.
Like other types of melanoma, subungual melanoma develops in melanocytes, the pigment cells that give skin its color. Unlike most types of skin cancer, subungual melanoma isn't related to sun exposure. Nail melanoma often shows up as a narrow brown or black streak or band on the nail.
Aside from looking like a changing mole, a melanoma on the foot can appear as a: Brown or black vertical line under a toenail. Pinkish-red spot or growth. New spot or growth where you injured your foot.
Treating Subungual Melanoma
If the melanoma spreads to other parts of the body, immunotherapy might be an option. If a doctor diagnoses subungual cancer early enough in its first stage, the survival rate is 97 percent at five years and 95 percent at ten years. The survival rate decreases for each stage.
Subungual melanoma is a serious type of skin cancer that develops under your nail. It most commonly appears as dark brown or black streaks on your nail. Early detection and prompt treatment yield the best outcomes.
Some fungal infections can darken the nail over time, especially if left untreated. The discoloration may appear brown, yellow-black, or gray, often accompanied by nail thickening or crumbling.
Additionally, wearing high heels or tight shoes, forcing the toes together and putting pressure on the nail can cause darkened toe nails. In some cases there appears to be a genetic factor so if a member of your family has an ingrown toenail, there is a greater chance you may develop one too.
Main Differences in Symptoms
A minor subungual hematoma usually heals over time without treatment. The trapped blood will eventually be reabsorbed, and the dark mark will disappear. This can take a number of months or years.
How Can You Tell If Your Toenail Is Dead? Some indications that your toenail is dead can include: changes in nail color from pink to black. The affected nail may at first appear to look reddish, purple or brown before it finally turns black.
Black toenail syndrome is a condition where one or more of the toenails turn black. The condition is very common in athletes, especially runners, and because of this, it is also called Runner's Toes.
Over time, untreated fungal infections can permanently change the shape of the affected nail.
The nail pigmentation associated with B12 deficiency is more frequent in patients with dark skin. The mechanism of hyperpigmentation is proposed to be decreased glutathione levels resulting in disinhibition of tyrosinase, an enzyme of melanogenesis leading to increased melanin synthesis.
Your health care provider may prescribe an antifungal cream, such as efinaconazole (Jublia) and tavaborole (Kerydin). You rub this product into your infected nails after soaking. These creams may work better if you first thin the nails.
Pain and Swelling: Trauma typically causes localized pain and swelling, which is usually absent with fungal infections. Nail Splitting: In cases of trauma, the nail might split or crack due to the injury, which is different from the thickening and crumbling seen in fungal infections.
Black fungal disease, also known as mucormycosis, is a severe infection that can be life-threatening if not treated in a timely manner. Therefore, if someone experiences symptoms such as nasal obstruction, fever, or flu-like symptoms, it is important to seek medical attention.
In some cases, black toenails can indicate underlying health issues. Conditions such as diabetes, heart disease, anemia, and kidney disease can all impact nail color due to poor circulation or oxygen deficiency.
The 5 key signs of melanoma, often remembered by the ABCDEs, are Asymmetry (uneven halves), Border irregularity (jagged edges), uneven Color (multiple shades), Diameter larger than a pencil eraser (about 6mm), and Evolving (changing in size, shape, color, or symptoms like itching/bleeding). Also watch for a sore that doesn't heal, new dark streaks under nails, or unusual sensations like itching or pain in a mole.
Equipment used for Nail Biopsy
For numbing your skin during the biopsy, a local anesthetic called 1% lidocaine solution is often used. This prevents you from feeling pain during the procedure.
Since the preliminary presentation of nail bed melanoma is brownish-black streak on the nail, it may often be misdiagnosed as benign conditions like onychomycosis, bacterial infection, subungual hematoma, pyogenic granuloma, subungual verruca, subungual exostosis, subungual hemorrhage, junctional nevi, glomus tumor, ...
It's possible to have melanoma and not know it. Some people may have types of melanoma, such as uveal melanoma, for many years. If you notice changes in your skin, seek medical attention as soon as possible. Some types of melanoma can go unnoticed for a long time, making it more challenging to treat.