A hangnail is a small, jagged piece of torn skin near the edge of the fingernail. Pulling or biting this loose skin often results in a tear that extends into the living tissue beneath. This action creates a wound, breaking the skin’s protective barrier and allowing common bacteria to enter the deeper layers. This injury triggers the body’s natural defense system, leading directly to the swelling and discomfort you are experiencing.
The Process of Inflammation and Swelling
The swelling around your finger is the localized immune response to the trauma of the torn skin. When tissue is damaged, cells at the injury site release chemical messengers, such as histamine, into the surrounding area. These chemicals cause blood vessels to dilate and become more permeable, increasing blood flow.
This increased permeability allows plasma fluid, proteins, and specialized immune cells, primarily neutrophils, to leak out of the bloodstream and accumulate in the injured tissue. This accumulation of fluid is termed edema, which causes the swelling. This process also results in the characteristic signs of inflammation: redness, warmth, and pain as the swelling puts pressure on nerve endings. This inflammatory phase typically lasts only a few days as the body works to clean the wound and begin repair.
Recognizing Signs of Infection
While initial swelling is inflammation, it can transition into a bacterial infection called acute paronychia. A sign of infection is the presence of pus, a thick, cloudy fluid that can be yellow or green, indicating a collection of dead white blood cells and bacteria. This pus may form a visible blister or abscess under the skin near the nail fold.
The pain often progresses from a mild ache to a persistent, throbbing sensation disproportionate to the injury size. Spreading redness extending past the immediate injury site and up the finger, known as cellulitis, signals the infection is moving deeper. Watch for red streaks tracing lines up your hand or arm (lymphangitis), which indicates the infection has entered the lymphatic system. Systemic symptoms like a fever or chills suggest the infection is spreading beyond the local area and require immediate medical evaluation.
Immediate At-Home Care
If the swelling is minor and you have not observed severe signs of infection, begin with gentle at-home care focused on cleansing. The most effective step is performing warm water soaks for 15 minutes, two to four times a day. Soaking encourages circulation and promotes drainage; you can add a small amount of mild soap or Epsom salt for additional cleansing benefits.
After soaking, gently pat the area dry and apply a thin layer of an over-the-counter antibiotic ointment to the wound. This helps prevent bacteria from colonizing the break in the skin barrier. Cover the area with a clean, dry bandage to protect it from further injury or contamination. Resist the urge to pick at the injury or attempt to squeeze or drain any collection of fluid, as this can push the infection deeper or introduce new bacteria.
When Professional Medical Attention is Necessary
Seek professional care if home treatment does not show improvement within 48 hours or if symptoms worsen rapidly. The presence of a visible, pus-filled blister or abscess causing pressure and pain is a clear indicator for a doctor’s visit. Do not wait if you observe red streaking moving up the finger or hand, as this signals a spreading infection.
A medical professional may diagnose the condition, often acute paronychia. If an abscess has formed, the doctor may perform a minor procedure called incision and drainage (I&D) to relieve pressure and remove the pus. This procedure often involves numbing the area and lifting the nail fold to allow the infection to drain. Depending on the severity, a doctor may also prescribe oral antibiotics to ensure the infection is cleared.