INTRODUCTION
Acne vulgaris is a chronic inflammatory disease of the pilosebaceous unit and is characterized by seborrhea, open/closed comedones, papules, pustules and nodulocystic lesions(1). The cause of acne vulgaris increased sebaceous gland activity, abnormal follicular hyper keratinization, microbial hyper-colonization of the follicular canal and increased inflammation(2). Lifestyle, diet, testosterone levels, gastrointestinal dysfunction, bacterial infection, and psychological factors play a role in the pathogenesis and development of acne. Exercise, even moderate activity such as walking, can help to treat both constipation and acne(3). Another disease affecting the brain and intestinal axis by inflammatory process is irritable bowel syndrome. Irritable bowel syndrome (IBS) is the most commonly diagnosed disease without an underlying organic pathology, characterized by the presence of abdominal pain or discomfort with variable bowel habits (4). Its prevalence is generally between 12–30% (5). IBS symptoms are identified in four subtypes according to Rome III criteria. Bristol Stool Scale (25) provides information about the consistency, thickness and amount of stool. Studies reveal that IBS is more common in women than men (6). IBS has been considered a brain-intestinal disease. In susceptible individuals (for example, those with a genetic predisposition or exposed to environmental factors), the association with psychological stress (eg anxiety, depression or somatization) and an infectious or inflammatory response can alter intestinal permeability, contributing to the onset of IBS symptoms (7). Depression and somatization can also lead to the development of IBS symptoms by mediating changes in intestinal permeability, immune system, and microbiome (7). Localized inflammation develops as the intestinal permeability increases, and then the number of inflammatory cells (histamine, tryptase, serotonin, TNF-, proteases and interleukins) increases (7). Although there are many data on acne and microbiota in the literature, data on acne and intestinal habits have not been determined. Normal functioning of gastrointestinal tract can influence benefit from oral treatment besides adverse events (7). The aim of this study is to evaluate the impact of bowel habits, IBS, physical activity, and dietary fiber intake in acne vulgaris patients.