A Consensus Panel of the American Academy of Dermatology (AAD) proposed criteria for the classification of acne in 1990. One conclusion of the Consensus Panel was that a purely quantitative definition of acne severity cannot be used, because of the variability in disease expression.


Types of Acne


Noninflammatory acne: presence of open or closed comedones only


Inflammatory acne: presence of papules, pustules and/or nodules (cysts)


Papules: inflammatory lesions < 5 mm in diameter


Pustules: inflammatory lesions < 5 mm in diameter, with a visible central core of purulent material


Nodules: inflammatory lesions >= 5 mm in diameter


Severity of Disease

Number of Lesions


few to several papules/pustules, AND no nodules


few to many comedones


several to many papules/pustules


few to several nodules


numerous and extensive comedones


numerous and/or extensive papules/pustules


many persistent or recurrent nodules


large and very extensive comedones


ongoing scarring


persistent purulent and/or serosanguinous drainage from lesions


presence of sinus tracts

very severe

acne conglobata


acne fulminans


acne inversa (follicular occlusion triad)



• Acne conglobata: a highly inflammatory condition with comedones, cysts, abscesses and draining sinus tracts. Healing occurs with resultant severe scarring.

• Acne fulminans: acute, febrile ulcerative acne with the sudden appearance of massive inflammatory and tender lesions of the back and chest which rapidly ulcerate and heal by scarring.


Additional factors affecting classification:

(1) psychosocial circumstances

(2) occupational difficulties

(3) inadequate therapeutic responsiveness


To read more or access our algorithms and calculators, please log in or register.