SummaryDespite acne being an almost universal condition in younger people, relatively little is known about its epidemiology. We sought to review what is known about the distribution and causes of acne by conducting a systematic review of relevant epidemiological studies. We searched Medline and Embase to the end of November 2011. The role of Propionibacterium acnes in pathogenesis is unclear: antibiotics have a direct antimicrobial as well as an anti-inflammatory effect. Moderate-to-severe acne affects around 20% of young people and severity correlates with pubertal maturity. Acne may be presenting at a younger age because of earlier puberty. It is unclear if ethnicity is truly associated with acne. Black individuals are more prone to postinflammatory hyperpigmentation and specific subtypes such as 'pomade acne'. Acne persists into the 20s and 30s in around 64% and 43% of individuals, respectively. The heritability of acne is almost 80% in first-degree relatives. Acne occurs earlier and is more severe in those with a positive family history. Suicidal ideation is more common in those with severe compared with mild acne. In the U.S.A., the cost of acne is over 3 billion dollars per year in terms of treatment and loss of productivity. A systematic review in 2005 found no clear evidence of dietary components increasing acne risk. One small randomized controlled trial showed that low glycaemic index (GI) diets can lower acne severity. A possible association between dairy food intake and acne requires closer scrutiny. Natural sunlight or poor hygiene are not associated. The association between smoking and acne is probably due to confounding. Validated core outcomes in future studies will help in combining future evidence.The clinical and histological features of acne, a chronic inflammatory disease of the pilosebaceous unit, are well described. Scarring is often present following inflammation 3 as illustrated in Figure 1. The pathophysiological events occurring in acne are also relatively well studied. Lesions start when keratinocytes lining the hair follicle desquamate creating a microcomedone. At puberty increased sebum production creates an environment that can sustain the colonization of Propionibacterium acnes. As P. acnes proliferates, inflammatory and chemotactic mediators are produced, which in turn drive inflammatory processes. 4Despite advances in understanding the pathophysiology of acne, much less appears to have been written about its epidemiology, which is strange considering that acne is almost universal in teenage years. Epidemiology not only describes the burden of disease in terms of incidence, prevalence and variations according to age, sex, social class, ethnic group and geography, but also has the potential to identify specific risk factors for disease occurrence or progression, which may be amenable to manipulation. Discovery of risk factors or factors that exacerbate existing disease could lead to appropriate primary or secondary preventative measures and treatments, which in turn could lead t...

SummaryAcne is estimated to affect 9Á4% of the global population, making it the eighth most prevalent disease worldwide. Epidemiological studies have demonstrated that acne is most common in postpubescent teens, with boys most frequently affected, particularly with more severe forms of the disease. This paper aims to provide an update on the epidemiology of acne worldwide. Recent general and institutional studies from around the world have shown that the prevalence of acne is broadly consistent globally (with the exception of specific populations, which are discussed). However, this review highlights that there is a wide range of disparate outcome measures being applied in epidemiology studies, and we emphasize the need to develop a widely accepted, credible, standard assessment scale to address this in the future. In addition we discuss special populations, such as those devoid of acne, as well as the impact of potential determinants of acne on disease epidemiology.Acne vulgaris, or acne, is a common condition with a wide range of potential harms and associated costs. The former include symptomatic discomfort, scarring, emotional and psychosocial distress, occupational consequences and potential psychiatric disturbances including depression and suicide. Identification of individuals at risk of these sequelae can contribute to reducing the morbidity associated with acne.The Global Burden of Disease Project estimates the prevalence of acne at 9Á4%, ranking it as the eighth most prevalent disease worldwide. 1,2This initiative established prevalence and disability data from primary research manuscripts and databases, and conducted subsequent data analysis with a Bayesian meta-regression methodology, providing a means to harmonize discordant data and to account for a lack of data in geographical, temporal or other demographic items.2 While this project uses primary research findings to inform global metrics, there has not been a recent attempt to collate and present the world literature on acne prevalence collected over the past decade and a half. The last such review of acne prevalence in both general and schoolaged populations comprised literature up to 1995.

IMPORTANCE Dermatologists prescribe more oral antibiotic courses per clinician than any other specialty, and this use puts patients at risk of antibiotic-resistant infections and antibiotic-associated adverse events. OBJECTIVE To characterize the temporal trends in the diagnoses most commonly associated with oral antibiotic prescription by dermatologists, as well as the duration of this use. DESIGN, SETTING, AND PARTICIPANTS Repeated cross-sectional analysis of antibiotic prescribing by dermatologists from January 1, 2008, to December 31, 2016. The setting was Optum Clinformatics Data Mart (Eden Prairie, Minnesota) deidentified commercial claims data. Participants were dermatology clinicians identified by their National Uniform Claim Committee taxonomy codes, and courses of oral antibiotics prescribed by these clinicians were identified by their National Drug Codes. EXPOSURES Claims for oral antibiotic prescriptions were consolidated into courses of therapy and associated with the primary diagnosis from the most recent visit. Courses were stratified into those of extended duration (>28 days) and those of short duration (Յ28 days). MAIN OUTCOMES AND MEASURES Frequency of antibiotic prescribing and associated diagnoses. Poisson regression models were used to assess for changes in the frequency of antibiotic prescribing over time. RESULTS Between 2008 and 2016 among 985 866 courses of oral antibiotics prescribed by 11 986 unique dermatologists, overall antibiotic prescribing among dermatologists decreased 36.6% (1.23 courses per 100 visits) from 3.36 (95% CI, 3.34-3.38) to 2.13 (95% CI, 2.12-2.14) courses per 100 visits with a dermatologist (prevalence rate ratio for annual change, 0.931; 95% CI, 0.930-0.932), with much of this decrease occurring among extended courses for acne and rosacea. Oral antibiotic use associated with surgical visits increased 69.6% (2.73 courses per 100 visits) from 3.92 (95% CI, 3.83-4.01) to 6.65 (95% CI, 6.57-6.74) courses per 100 visits associated with a surgical visit (prevalence rate ratio, 1.061; 95% CI, 1.059-1.063). CONCLUSIONS AND RELEVANCE Continuing to develop alternatives to oral antibiotics for noninfectious conditions, such as acne, can improve antibiotic stewardship and decrease complications from antibiotic use. In addition, the rising use of postoperative antibiotics after surgical visits is concerning and may put patients at unnecessary risk of adverse events. Future studies are needed to identify the value of this practice and the risk of adverse events.

Summary Background Oral propranolol is widely prescribed as first‐line treatment for infantile haemangiomas (IHs). Anecdotally, prescribing practice differs widely between centres. Objectives The Propranolol In the Treatment of Complicated Haemangiomas (PITCH) Taskforce was founded to establish patterns of use of propranolol in IHs. Methods Participating centres entered data on all of their patients who had completed treatment with oral propranolol for IHs, using an online data capture tool. Results The study cohort comprised 1097 children from 39 centres in eight European countries. 76·1% were female and 92·8% had a focal IH, with the remainder showing a segmental, multifocal or indeterminate pattern. The main indications for treatment were periocular location (29·3%), risk of cosmetic disfigurement (21·1%) and ulceration and bleeding (20·6%). In total 69·2% of patients were titrated up to a maintenance regimen, which consisted of 2 mg kg−1 per day (85·8%) in the majority of cases. 91·4% of patients had an excellent or good response to treatment. Rebound growth occurred in 14·1% upon stopping, of whom 53·9% were restarted and treatment response was recaptured in 91·6% of cases. While there was no significant difference in the treatment response, comparing a daily maintenance dose of < 2 mg kg−1 vs. 2 mg kg−1 vs. > 2 mg kg−1, the risk of adverse events was significantly higher: odds ratio (OR) 1 vs. adjusted OR 0·70, 95% confidence interval (CI) 0·33–1·50, P = 0·36 vs. OR 2·38, 95% CI 1·04–5·46, P = 0·04, Ptrend < 0·001. Conclusions The PITCH survey summarizes the use of oral propranolol across 39 European centres, in a variety of IH phases, and could be used to inform treatment guidelines and the design of an interventional study.

No abstract