Common Causes of Discoloration
Many instances of toenail discoloration stem from physical injury. A subungual hematoma occurs when blood accumulates beneath the nail plate, appearing as a dark spot or bruise. This typically results from direct trauma, such as stubbing a toe, or from repetitive pressure caused by ill-fitting footwear during activities like running or hiking. The trapped blood can spread, sometimes causing pain due to pressure under the nail.
Fungal infections, medically known as onychomycosis, are another frequent contributor to changes in nail appearance. While these infections commonly cause nails to become yellow, brown, or thickened, severe or long-standing cases can sometimes lead to black discoloration. The nail may also become brittle, crumbly, or lifted from the nail bed.
Less Common Causes of Discoloration
While less common, certain serious conditions can also cause black toenail discoloration. Subungual melanoma, a type of skin cancer, can appear as a black or brown streak under the nail. This condition is serious and requires prompt evaluation, as early detection improves treatment outcomes. Any new or changing dark streak under a nail should be examined by a medical professional.
Some medications can cause changes in nail color as a side effect. Certain chemotherapy drugs, for example, are known to cause nail darkening. Similarly, some antibiotics or other systemic medications can cause changes in nail pigmentation. These changes are typically temporary and resolve after discontinuing the medication, though consulting a doctor is advisable.
On rare occasions, underlying health conditions may contribute to nail changes, though direct black discoloration is less common than other nail symptoms. Systemic diseases can sometimes affect nail health, leading to various changes in texture, shape, or color. These instances are typically accompanied by other, more prominent symptoms of the underlying condition.
When to Seek Medical Attention
Seek medical attention if a black toenail causes persistent or worsening pain, especially if discomfort does not subside after a minor injury. Discoloration that appears to spread, changes in shape, or occurs without any clear history of trauma requires evaluation. These signs could indicate a more serious underlying issue.
Additional warning signs include any indications of infection, such as redness, swelling, or pus around the nail. If the black area extends onto the cuticle or the skin surrounding the nail, this could be a concerning symptom. If you have a family history of melanoma or notice a changing lesion under your nail, seek prompt medical consultation to rule out serious conditions.
Also seek medical attention if the nail begins to detach from the nail bed or falls off completely, particularly if there is no clear cause. These symptoms suggest that the nail bed may be compromised or that an ongoing issue needs assessment. A healthcare provider can accurately diagnose the cause of the discoloration and recommend appropriate treatment.
Preventive Measures and Home Care
Preventing black toenails involves simple measures. Wearing proper footwear is important; shoes should be well-fitting and provide adequate space in the toe box to prevent repetitive friction or pressure on the nails. Trimming toenails straight across helps prevent ingrown nails and reduces the risk of trauma, particularly during physical activities. Protecting feet with appropriate gear during sports or work can also minimize injury.
For minor subungual hematomas resulting from acute trauma, basic home care is effective. The RICE method, which involves rest, ice, compression, and elevation, can help manage swelling and discomfort immediately after an injury. Keeping the affected area clean is important to prevent secondary infections. Avoid attempting to drain a hematoma at home without professional guidance, as this can introduce infection.