There is perhaps nothing that disrupts the serenity and beauty of a foot more than an ugly blackened toenail. (Well, there may be a few more disruptive things, but black toenails are pretty icky, all the same.) Dark discolorations in the toenail don’t always have to be black, either. They may also look purplish or brown, two other colors that don’t go very well with the foot’s natural décor.

The cause of these discolorations is usually pretty straightforward-generally they’re from a blood clot or bruising under the toenail, most likely caused by that time you dropped your toolbox onto your foot, or possibly the way you keep jamming your toes during football practice.

However, occasionally the cause may be something more severe, such as melanoma (or skin cancer) that’s growing under the nail. In this case, you’re likely to see the discoloration as a brown or black streak under the nail. This type of melanoma is more likely to occur in people with dark skin (it accounts for about 30-40% of melanomas in the non-white population), although it strikes both men and women fairly equally.

Black toenails may also occur because of fungal infections, really bad ingrown toenails (often when they’re recurring), or other health concerns, although these tend to be more rare.

Obviously, the main symptom of a black toenail is… well… a black toenail. Or, as previously mentioned, the toenail may appear purple or brownish. If the discoloration is caused by bruising under the nail, the bleeding may cause some painful pressure to develop in the area, since the blood doesn’t really have an easy escape route.

Melanomas will tend to show up as a streak under the nail, usually dark but occasionally white. However, because they can show up in any form, it’s usually a good idea to treat any nail discoloration with suspicion-checking with a foot doctor is a good idea. Be very suspicious if you can’t remember injuring the toe in any way, if the streak doesn’t disappear over time, or if it gets bigger.

Your podiatrist will likely examine the area and inquire about recent injuries to your foot that might be a factor in the toenail discoloration. If melanoma is suspected, obtaining a biopsy of the tissue is really the only way to find out for sure if the tissue is cancerous. It may be no fun, but early detection makes treatment that much easier, and often more successful.

Bruising under the toenail is most likely to disappear over time, although you may opt to have your podiatrist relieve the pressure under your nail caused by the bleeding. Avoiding tight shoes and allowing for extra room in the toe box is likely to make your toenail more comfortable while it’s healing.

Melanomas will require more aggressive treatment. If the disease is caught early enough, your podiatrist may be able to effectively rid you of the problem by just cutting out the melanoma itself. However, in more advanced stages, it may be necessary to amputate the affected toe. Removing nearby lymph nodes may be needed to prevent the spread of the cancer, and treatment may also involve other cancer-fighting methods, such as chemotherapy.