Onychocryptosis, commonly known as an ingrown toenail, occurs when the edge of the nail plate grows into the surrounding skin of the toe, typically the big toe. This mechanical irritation creates a wound that allows the entry of common bacteria found on the skin, leading to inflammation and discomfort. When neglected, this condition progresses into a worsening cycle of pain, deeper infection, and potentially severe complications.
Progression of Local Symptoms
The skin along the nail margin, known as the nail fold, begins to exhibit increased redness, swelling, and persistent pain, especially when pressure is applied, such as when wearing shoes. The continuous pressure from the imbedded nail spike prevents the skin from healing and provides a constant entry point for microorganisms.
As the body attempts to repair the wound, hypergranulation tissue begins to form. This tissue is soft, raised, and bright red because it contains a dense network of new, fragile blood vessels. The formation of this fleshy tissue intensifies the problem by further pushing the skin over the nail edge, trapping moisture, and making the area tender and prone to bleeding.
This chronically inflamed tissue and persistent bacterial colonization marks a transition to a more advanced stage. The pain often becomes throbbing and can make walking difficult, significantly impacting daily mobility. The toe may also feel warm to the touch, indicating ongoing inflammation and localized infection.
Deepening and Spreading Infection
If the infection is not resolved, bacteria can penetrate deeper into the soft tissues, often resulting in cellulitis. Cellulitis is a condition where the infection spreads into the subcutaneous fat and connective tissue. It is characterized by redness radiating outward from the toe, swelling extending beyond the nail fold, and increased warmth.
An abscess may also occur, forming from a significant accumulation of pus (dead white blood cells and bacteria). This collection of pus creates a tense, painful pocket within the toe that requires medical drainage to relieve pressure and clear the infection. The abscess and cellulitis make the toe severely tender, sometimes leading to persistent drainage and a foul odor.
Chronic inflammation and infection can also lead to the overgrowth of surrounding skin tissue, known as lateral nail-fold hypertrophy. This excess tissue permanently alters the shape of the toe and can make the issue recurrent, even if the nail is temporarily trimmed. At this stage, the pain and swelling are often so severe that wearing closed footwear becomes impossible, limiting daily function.
Severe Systemic Complications
While the infection is typically contained in the foot for the general population, consequences can become life-threatening for individuals with underlying health issues. Those with diabetes, peripheral vascular disease, or a compromised immune system are at high risk for rapid progression to severe systemic complications. Diabetes causes nerve damage (neuropathy) which may mask the pain, and poor circulation hinders the body’s ability to fight infection and slows wound healing.
The infection, particularly in high-risk individuals, can move beyond the soft tissue and infect the underlying bone, a serious condition called osteomyelitis. This deep bone infection is difficult to treat and requires weeks of powerful antibiotics, often administered intravenously, and sometimes surgical removal of the infected bone tissue. Untreated severe infection can also lead to gangrene, the death of tissue due to a lack of blood supply or overwhelming bacterial infection.
In the most severe cases, the localized infection can enter the bloodstream, resulting in a systemic infection known as sepsis. Sepsis is a body-wide, life-threatening reaction that can lead to organ failure and death if not treated immediately. Severe bone infection or gangrene may ultimately necessitate toe or foot amputation to stop the spread of the infection.
When to Seek Professional Intervention
While mild ingrown toenails without infection can sometimes be managed with careful at-home care, professional medical attention is required when the condition shows specific signs of worsening. Any indication of pus or chronic discharge, increasing redness that spreads beyond the nail fold, or significant warmth in the toe signals a bacterial infection that needs a doctor’s evaluation. If the pain becomes intense, throbbing, or makes walking difficult, home treatment is no longer sufficient to manage the problem.
Seek medical care immediately if a fever or chills accompany the local toe symptoms, as these are signs that the infection is becoming systemic. Any individual with diabetes, poor circulation, or a weakened immune system should consult a doctor or podiatrist at the first sign of an ingrown toenail, regardless of how minor it appears.