Pain along the side of your nail is almost always caused by pressure or inflammation where the nail edge meets the surrounding skin. That strip of skin, called the lateral nail fold, is vulnerable to irritation from an ingrown nail, a hangnail, an infection, or simply shoes that squeeze your toes. Most cases resolve at home within a few days, but some need professional treatment.
Ingrown Nails: The Most Common Cause
An ingrown nail develops when a sharp edge or spicule of the nail plate digs into the soft skin alongside it. The nail essentially acts as a foreign body, gradually piercing the tissue and triggering inflammation, swelling, and pain. Toenails are affected far more often than fingernails, and the big toe is the usual culprit.
Several things set this up. Cutting the nail too short or rounding the corners can leave a small spur that grows into the skin fold. Shoes with a narrow toe box press the nail into the surrounding tissue, and over time that constant pressure causes the skin to break down. Excessive sweating softens the nail fold, which is why ingrown nails are especially common in teenagers and athletes. Obesity can deepen the groove around the nail, making it easier for the edge to embed. Some people simply have nails that curve more than usual (sometimes called pincer nails), which raises the risk regardless of footwear or trimming habits.
Early on, you’ll notice tenderness, redness, and mild swelling along one side of the nail. If the nail continues to push into the skin, the area can become infected: you may see pus, feel throbbing pain, and notice that the swollen tissue starts to grow over the nail edge.
Paronychia: Infection of the Nail Fold
Paronychia is the medical term for an infection of the skin right next to the nail. The main symptom is a painful, red, swollen area around the nail, often at the cuticle or at the site of a hangnail or other small injury. With a bacterial infection, pus-filled blisters can form along the nail fold.
The infection starts when something breaks the seal between the nail and the skin. That break can be surprisingly minor: a hangnail, a torn cuticle, nail biting, aggressive manicuring, or placing artificial nails. Once bacteria or yeast get into the moist crevice alongside the nail, they multiply quickly. In more advanced cases, pus collects under the skin of the lateral fold and forms a small abscess.
Acute vs. Chronic Paronychia
Acute paronychia comes on fast, usually affecting one finger or toe after a specific injury. It’s typically bacterial, and the swelling and pain develop over a day or two. Chronic paronychia is different. It builds slowly over weeks, often in people whose hands are frequently wet or exposed to irritants (dishwashers, bartenders, healthcare workers). Yeast is a common contributor in chronic cases, and the nail fold stays puffy and tender without the dramatic redness of an acute infection. If chronic paronychia affects only a single digit and won’t resolve, that warrants a medical evaluation to rule out other causes.
Hangnails and Minor Trauma
A hangnail is a small, torn strip of skin along the nail edge. It’s not actually part of the nail itself, but it can be surprisingly painful because the skin around your nail is rich in nerve endings and tightly attached to the tissue beneath it. Pulling or biting a hangnail often tears the skin deeper than intended, creating an opening for bacteria. What started as a minor annoyance can quickly become a red, swollen paronychia if the torn skin isn’t kept clean.
Other minor trauma works the same way. Jamming your finger in a door, catching a nail on fabric, or picking at the skin alongside the nail all disrupt the protective barrier and invite infection.
Fungal Nail Infections
Fungal infections can also cause side-of-nail pain, though they tend to develop more gradually than bacterial infections. The most common type starts at the tip or sides of the nail and spreads inward. You’ll notice the nail turning white, yellow, or brown, becoming thicker, and eventually separating from the nail bed. As the nail thickens and distorts, it can press into the lateral fold and cause persistent soreness. Crumbling or cracked nails are another hallmark. Fungal infections don’t resolve on their own and typically need antifungal treatment.
What You Can Do at Home
If the pain is mild and there’s no pus, swelling that’s spreading, or fever, home care often works well. Warm water soaks are the standard first step: submerge the affected finger or toe for about 20 minutes, a few times a day. Adding Epsom salt to the water can help reduce inflammation. After soaking, you can gently massage the skin near the nail to improve circulation and encourage any fluid to drain.
For an ingrown toenail, switch to shoes with a roomier toe box or open-toed shoes while it heals. Avoid trimming the nail shorter in an attempt to dig out the ingrown edge, as this usually makes it worse. Instead, let the nail grow out past the skin fold. Keeping the area clean and dry between soaks helps prevent bacterial buildup.
For a hangnail, resist the urge to pull it. Clip it cleanly with sharp nail scissors as close to the base as possible, then apply a small amount of antibiotic ointment and cover it with a bandage until the skin closes.
Signs That Need Professional Care
If soaking and basic care don’t improve things within two to three days, or if symptoms are getting worse, the infection likely needs more than home treatment. Red streaks extending away from the nail, increasing pain, a visible pocket of pus, or warmth and swelling that spreads beyond the immediate nail area all suggest an abscess may be forming. An abscess needs to be drained by a healthcare provider; antibiotics alone won’t clear a walled-off pocket of pus.
If more than one finger or toe is affected at the same time, that can signal a broader issue worth investigating rather than a simple local infection.
Extra Caution With Diabetes
People with diabetes face higher stakes with any nail or foot problem. Reduced blood flow and nerve damage in the feet mean infections can progress faster and heal more slowly. An ingrown toenail that would be a minor nuisance for most people can lead to serious complications in someone with diabetes. If you have diabetes and notice pain along the side of a toenail, have it evaluated by a podiatrist rather than managing it at home. Soaking your feet is generally discouraged with diabetes because it can dry and crack the skin, creating new entry points for infection.
Preventive nail care matters here: trim nails straight across, smooth sharp edges with a file, and wear shoes that fit well. If you can’t see or easily reach your feet, a podiatrist can handle routine trimming for you.
Preventing Recurrence
Most side-of-nail pain comes back because the underlying habit or fit issue hasn’t changed. Trim your nails straight across rather than rounding the corners, and avoid cutting them too short. Wear shoes that give your toes enough room. Keep your hands and cuticles moisturized to prevent hangnails, and avoid biting or picking at the skin around your nails. If you get manicures or pedicures, make sure instruments are properly sterilized, since cuticle pushing and trimming are common entry points for infection.