A black toenail can be concerning, but it’s often the result of a minor issue. Understanding the potential causes and appropriate steps is crucial for managing this common condition.
Understanding Why Your Toenail Turns Black
A common reason for a black toenail is trauma, leading to a subungual hematoma. This occurs when blood vessels beneath the nail rupture, causing blood to pool and appear dark. It can result from a single, acute injury, such as stubbing a toe or dropping a heavy object on it, or from repetitive microtrauma, like the constant pressure from ill-fitting shoes during activities such as running or hiking. The trapped blood often causes pain and tenderness.
Fungal infections, medically known as onychomycosis, can also cause toenail discoloration. Fungi thrive in warm, moist environments and can lead to thickening, brittleness, and a buildup of debris under the nail, which contributes to a dark appearance. While typically presenting as white or yellow, some fungal infections can darken the nail over time if left unaddressed.
Less commonly, a black toenail might signal more serious conditions. Subungual melanoma, a rare form of skin cancer, can manifest as a dark streak or spot under the nail that does not resolve or grow out. Unlike a hematoma, melanoma under the nail is not caused by trauma and may involve pigment spreading to the surrounding skin. Certain underlying health conditions, such as diabetes, kidney disease, or some medications, can also contribute to nail discoloration.
When a Doctor’s Visit is Necessary
While many black toenails resolve on their own, certain signs indicate the need for medical evaluation. Seek medical advice if the black discoloration appeared without any known injury, as this could suggest a more serious underlying cause. Increasing pain, swelling, warmth, or redness around the nail are signs of a potential infection, warranting immediate medical attention. Pus draining from the area or a red streak extending from the site also indicates an infection.
A doctor’s visit is also important if the discoloration spreads, changes in size or color over time, or extends beyond the nail onto the surrounding skin. These could indicate subungual melanoma, a condition that requires prompt diagnosis and treatment. If the black area covers more than half of the toenail, or if the nail is lifting or separating from the nail bed, a medical professional should assess it. Individuals with diabetes or other health conditions affecting circulation should consult a podiatrist for any toenail changes, as they are more susceptible to complications.
Caring for Your Toenail at Home
For black toenails resulting from minor trauma without severe pain or signs of infection, home care can aid recovery. Resting the affected foot and elevating it helps reduce swelling and discomfort. Applying ice wrapped in a cloth to the injured area minimizes swelling and pain. Over-the-counter pain relievers, such as acetaminophen or ibuprofen, can also manage discomfort.
Ensuring proper footwear that does not press on the injured toe can prevent further irritation. If the nail is loose or partially detached, keeping the area clean and dry is important to prevent infection. A non-stick bandage can protect the nail. As the nail grows, the black area from a subungual hematoma will gradually move forward and eventually grow out, which can take several months. The old, discolored nail may eventually fall off as the new nail grows in underneath.
Preventing Future Black Toenails
Preventing black toenails often involves simple adjustments to footwear and nail care practices. Selecting properly fitting shoes is crucial, ensuring ample space in the toe box to prevent toes from pressing against the front or sides. Ill-fitting shoes, whether too tight or too loose, can cause repetitive trauma to the toenails. Athletes, particularly runners, should invest in sport-specific shoes that provide adequate cushioning and impact absorption.
Trimming toenails correctly also plays a role in prevention. Nails should be cut straight across, avoiding rounded edges, and not too short. Regular trimming prevents them from becoming too long and hitting the inside of shoes, which can lead to injury. Wearing moisture-wicking socks helps keep feet dry, reducing friction and preventing fungal growth by limiting the warm, moist environment fungi prefer. Taking precautions during activities that might cause toe trauma, such as wearing closed-toe shoes when working with heavy objects, also helps protect the nails.