What causes an ingrown toenail on the big toe?

Generally speaking, a large toenail refers to the big toe's nail. In most cases, ingrown toenails are caused by factors such as ill-fitting shoes, improper walking posture, nail trauma, paronychia, or onychomycosis. It is recommended to seek medical attention promptly, identify the underlying cause, and receive appropriate treatment under a doctor’s guidance. Specific analysis is as follows:

1. Ill-Fitting Shoes

If your feet are relatively wide but you wear narrow or small-sized shoes, the big toe may experience excessive pressure over time, leading to nail deformation. The deformed nail continues to grow inward, resulting in the aforementioned condition. It is advised to trim the deformed nail properly and switch to well-fitting shoes, which can help alleviate discomfort to some extent.

2. Improper Walking Posture

Long-term incorrect walking posture can lead to uneven pressure on the toenail, eventually causing it to grow into the surrounding skin. This may be accompanied by symptoms such as redness, swelling, pus formation, and exudation. After cleaning hands thoroughly, gently express any accumulated pus and disinfect the area with iodophor. Paying attention to correcting walking posture in daily life can help relieve symptoms.

3. Nail Trauma

If the big toenail suffers external injury such as being crushed, it may result in nail deformation and cause the nail to grow into the flesh. Follow your doctor’s instructions for treatment using medications such as erythromycin ointment, mupirocin ointment, or itraconazole capsules.

4. Paronychia

If the soft tissue around the nail groove is accidentally injured while trimming the big toenail and not properly disinfected afterward, bacterial proliferation may occur, leading to infection and inflammation—known as paronychia. Symptoms include local redness, swelling, heat, pain, and the nail growing into the skin, possibly progressing to abscess formation. Patients should use medications such as fusidic acid sodium ointment, chlorhexidine acetate solution, or ichthammol ointment as directed by a physician to improve the condition.

5. Onychomycosis (Fungal Nail Infection)

Due to low immunity, individuals may be prone to bacterial or fungal infections that trigger onychomycosis, causing the nail to become ingrown. Other symptoms may include thickened nails, scaling, brittleness, and deformity. Under medical supervision, medications such as amoxicillin capsules, roxithromycin capsules, or ciclopirox cream may be used to relieve discomfort.

It is recommended to maintain a light diet, avoid smoking and alcohol, keep warm, and refrain from consuming irritating foods such as shrimp, chili peppers, and ginger. Maintaining a positive mindset also contributes to recovery and overall health.