This is a severe, ulcerative form of acne distinguished by its abrupt onset, systemic symptoms (fever, arthralgias), and progression to ulceration and scarring.
A furuncle (boil) is a solitary, deep bacterial abscess of a hair follicle, whereas nodular acne involves multiple inflammatory nodules and cysts without the same degree of acute suppuration.
Nodular rosacea (rosacea fulminans) can cause inflammatory nodules, but it is distinguished by the complete absence of comedones and a background of flushing and erythema.
This is an explosive onset of nodules and pustules on the central face in young women, but critically, it lacks the comedones that are essential for a diagnosis of acne.
