High Frequency of Obesity in Acne Keloidalis Nuchae Patients: A Hypothesis from a Brazilian Study.

Acne keloidalis nuchae (AKN) is a chronic inflammatory condition that almost exclusively affects the occipital and nape areas. Although not completely understood, its etiopathogenesis seems to be multifactorial, including association with metabolic syndrome (MetS). Despite being commonly seen in patients with MetS, obesity per se as a possible related factor for AKN has yet to be studied. The aim of this study was to evaluate the relationship between obesity and AKN in a series of patients. Eight male patients, with a median age of 38 years (range 15-48), were included. Overweight/obesity was found in 8/8 (100%), with median BMI of 32.2 (range 27.7-43.85 kg/m2), including 2 patients with class 3 obesity. We hypothesize adipose tissue accumulation in the nape, the only moving part of the scalp, leads to redundant skin folds, more friction, and inflammation, triggering AKN. This paper highlights the possible relationship between AKN and overweight/obesity, hypothesizing a mechanism for their contribution to the etiopathogenesis of this scalp disorder. To the best of our knowledge, this is the first study focused specifically in this association. While general physicians should pay attention to the appearing of AKN in overweight/obese patients, dermatologists must be aware that AKN patients should be assessed beyond the skin.