What is the primary cause of paronychia?

The primary cause of paronychia is a bacterial infection. Paronychia is an inflammation of the paronychia, the tissue surrounding the nail. This condition often occurs when the skin around the nail is damaged, providing an entry point for bacteria, particularly Staphylococcus aureus.

When the surrounding skin is broken or irritated—such as from nail biting, manicuring, or even hangnails—bacteria can invade the area, leading to an infection. Symptoms of paronychia typically include redness, swelling, pain, and sometimes pus formation around the nail. While fungal infections can also occur in and lead to similar symptoms, they are not the primary cause; instead, they can develop as a secondary issue or in cases of chronic paronychia, which is often underlain by an initial bacterial infection.

Viral and parasitic infections are relatively rare causes of paronychia, making them less relevant in the context of this question. Understanding the primary role of bacterial infection helps in both the prevention and treatment of this common nail disorder.