The pain on the side of a toenail, despite not being ingrown, can be a puzzle for many. An ingrown toenail, or onychocryptosis, is characterized by the nail edge growing into the surrounding skin, causing inflammation, redness, and often, a painful infection. When those classic signs are absent, yet the pain persists, other culprits must be considered.
One of the most common reasons for this type of pain is simple pressure. The toenail and the skin around it are sensitive to external forces. Wearing shoes that are too tight, especially in the toe box, can compress the sides of the nail, leading to a dull ache or sharp pain. This pressure can also be exacerbated by activities like running, hiking, or even prolonged standing, where the foot is constantly pushing against the shoe. The pain might not be caused by the nail itself, but rather by the soft tissue being squeezed between the nail and the shoe’s inner wall.
Another potential cause is a subungual hematoma, which is a bruise under the toenail. This can happen from a direct impact, like stubbing a toe, or from repetitive micro-trauma, such as a long-distance run where the nail repeatedly hits the inside of the shoe. While a large hematoma is usually obvious due to the dark, purplish discoloration under the nail, a smaller or less severe bruise might just present as localized pain on the side of the nail. The pressure from the trapped blood can cause significant discomfort, and it may take weeks for the bruise to grow out with the nail.3
Fungal infections, or onychomycosis, can also cause pain and discomfort on the sides of the nail. While a fungal infection is more commonly associated with a change in the nail’s color, thickness, and texture, it can also cause the nail to lift from the nail bed (onycholysis). When the nail separates, it can become a breeding ground for bacteria and debris, leading to inflammation and pain along the nail edges. The nail itself may also become brittle and crumbly, which can create sharp edges that irritate the surrounding skin.
Beyond these common issues, there are other, less frequent causes. A small splinter or foreign body lodged under the nail or in the nail fold can cause a localized, sharp pain. Similarly, a bony spur or an exostosis (an abnormal bone growth) under the nail can put pressure on the nail bed, causing pain. This is more common on the big toe and may require a medical evaluation.
Nail psoriasis is another condition that can mimic an ingrown toenail. Psoriasis can affect the nails, causing pitting, ridges, and discoloration. It can also cause the nail to thicken and lift from the nail bed, leading to pain and discomfort along the sides. Unlike a fungal infection, psoriatic nails are typically not discolored by a fungus, but rather by the underlying inflammatory process.
In some cases, the pain might not even be related to the nail itself. Conditions like gout, arthritis, or a bunion can cause referred pain that is felt on the side of the toe. Nerve compression, or a neuroma, can also cause a burning or shooting pain that might be mistaken for a nail problem.
When faced with this type of pain, the first step is to assess the situation. Is there any redness, swelling, or pus? If so, it might be a mild infection that has not yet progressed to an ingrown toenail. If there is no visible sign of infection, consider the recent history. Have you changed your footwear? Have you been engaging in new or strenuous physical activity? Have you had any recent trauma to the toe?
For at-home care, the focus is on relieving pressure and promoting healing. Soaking the foot in warm, soapy water can help soften the skin and reduce inflammation. Choosing properly fitting shoes with a wide toe box is crucial. If the pain is due to a suspected bruise, giving the toe time to heal and avoiding further impact is the best course of action.
However, if the pain is severe, persistent, or accompanied by any signs of infection (like spreading redness or pus), it is essential to consult a healthcare professional, such as a podiatrist. A podiatrist can accurately diagnose the underlying issue and recommend appropriate treatment, which may range from trimming the nail correctly to prescribing anti-fungal medication or, in rare cases, a minor surgical procedure to address a bone spur or other structural issue.
The pain on the side of a toenail that is not ingrown is a nuanced problem with a variety of potential causes. From ill-fitting shoes and minor trauma to fungal infections and underlying medical conditions, the reason for the discomfort can be complex. By understanding the different possibilities and taking a proactive approach to care, one can effectively address this common and often overlooked source of foot pain.