Red toenails can be a concerning observation, often signaling a disruption in the normally clear or pinkish nail bed. This discoloration typically indicates a reaction beneath the nail plate, such as localized bleeding, an inflammatory response, or an active infection. Understanding the cause of the redness is the first step toward appropriate care, as the underlying issue can range from a minor injury to a sign of a more widespread health condition. This article explores the most common physical, infectious, and internal reasons for toenail redness.
Mechanical Causes of Redness
The most frequent cause of red or dark discoloration beneath a toenail is physical trauma, resulting in a subungual hematoma. This occurs when an acute impact, such as stubbing a toe or dropping a heavy object, causes blood vessels in the nail bed to rupture. The resulting collection of blood becomes trapped between the nail plate and the nail bed, creating a visible red, purple, or black bruise.
Chronic mechanical stress can also lead to this condition, often seen in runners or hikers who wear ill-fitting footwear. Repetitive microtrauma causes constant friction or pressure, damaging small capillaries over time. The pain associated with a subungual hematoma is due to the pressure of the blood accumulation under the rigid nail plate.
Infectious Causes in the Nail Bed
Redness around the toenail can indicate an active infection, most commonly presenting as paronychia. This is an inflammation of the nail folds, the skin surrounding the nail plate, which becomes painful, warm, and distinctly red. Acute paronychia is typically caused by a bacterial invasion, often Staphylococcus aureus, entering through a break in the skin barrier created by a minor injury or an ingrown nail.
This bacterial form develops rapidly, often within a few hours, and may present with a collection of pus beneath the skin fold. Chronic paronychia is usually linked to persistent exposure to moisture or irritants, sometimes involving a fungal organism like Candida. While a fungal nail infection (onychomycosis) primarily causes nail thickening and yellowing, redness appears when the surrounding skin becomes inflamed or a secondary bacterial infection takes hold.
Redness from Inflammatory and Systemic Conditions
Persistent toenail redness can be a symptom of internal inflammation or systemic disease. One common sign is the appearance of splinter hemorrhages, which are thin, reddish-brown lines running lengthwise under the nail. These lines are caused by damaged capillaries leaking blood into the nail bed.
Dermatological conditions like psoriasis can manifest in the toenails with redness, often presenting as “oil drop” or “salmon patches” beneath the nail plate. Nail psoriasis is an autoimmune process where the body attacks the nail matrix and bed, leading to distinct areas of red-pink discoloration.
Systemic issues, including vasculitis or infectious endocarditis, can also cause splinter hemorrhages by disrupting blood flow and damaging vessels throughout the body. When multiple toenails show this pattern without trauma, a medical evaluation is recommended to rule out underlying health concerns.
When to Seek Professional Medical Advice
While many causes of toenail redness resolve on their own, certain symptoms require prompt medical attention. You should see a healthcare provider if the redness is accompanied by severe, throbbing pain that does not subside after a few days, or if the discoloration covers more than half of the nail.
Signs of a worsening infection, such as fever, red streaks extending from the toe up the foot, or the presence of pus, signal a potential need for antibiotics or drainage. Individuals with diabetes or other conditions that compromise circulation or nerve function should seek professional care immediately for any new or persistent nail change.
Any new dark line or spot under the nail that appears without injury should be evaluated to exclude rare but serious conditions like subungual melanoma. Persistent redness or discoloration that does not improve over time also warrants a medical diagnosis to identify any underlying inflammatory or systemic cause.