What condition is referred to as acne vulgaris?

Acne vulgaris is specifically characterized by the inflammation of the sebaceous glands, which are responsible for producing oil in the skin. This condition typically occurs when the sebaceous glands become overactive and lead to the clogging of hair follicles with excess oil and dead skin cells. This clogged environment is conducive to bacterial growth, resulting in the characteristic pimples, blackheads, and sometimes cysts associated with acne.

In contrast, other conditions mentioned do not relate directly to acne. Inflammation of the immune system involves broader immune responses, an infection of the nail bed is known as paronychia, and dermatitis of the scalp refers to a different skin condition affecting the scalp. Acne vulgaris is thus directly linked to the sebaceous glands and is widely recognized by the symptoms that arise from their inflammation, making the correct response the one that identifies this precise cause.