Causes of ingrown toenail formation

Ingrown toenails (also known as icterus nails or ingrown nails) are a common foot problem in which the edge of the nail grows abnormally and embeds into the surrounding skin. It often occurs on the big toe and can cause pain, redness, swelling, suppuration, and even paronychia infection.

Ingrown toenails can be divided into two main categories: congenital and acquired. Acquired toenails are more common and are often caused by a combination of lifestyle habits.

Congenital factors include:
• Hereditary pincer nail, where the nail is excessively bent and embeds itself into the flesh.
• An excessively wide nail bed or abnormal development of the toe bones can cause the nail edges to grow unevenly.
• Certain genetic conditions, such as psoriasis or periungual eczema, can alter the shape of the nails.

Acquired factors are more common, encompassing unhealthy daily habits:
• Improper nail trimming: cutting nails too short, with rounded edges, or leaving sharp points can stimulate skin growth that covers the nail.
• Wearing tight or pointed shoes: Long-term pressure on the toes causes the edges of the nails to curl inward, especially with high heels or sneakers.
• Foot hygiene problems: Excessive sweating of the feet, a humid environment that breeds bacteria, or neuropathy in diabetic patients that reduces pain sensation and makes them easy to overlook.
• Repeated injuries: kicking a ball, running, or being crushed by heavy objects can cause abnormal nail growth.
• Fungal nail infection (onychomycosis): The nail thickens and deforms, increasing the risk of ingrown toenails.
• Other factors: obesity increases foot pressure, pregnancy hormone changes, or age-related slow nail growth.