This medical condition is known as an abscess or subcutaneous infection, and it usually appears as a red, swollen, painful area that feels warm to the touch. It occurs when bacteria enter the skin and the body responds by forming a collection of pus as a defense mechanism. The most commonly affected areas include the back, shoulders, neck, and thighs.
The main causes of an abscess are small skin wounds, ingrown hairs, poor hygiene, or a weakened immune system. In some cases, the infection can develop without an obvious cause. People who sweat excessively or have sensitive skin are at higher risk.
