Granuloma annulare (GA) is a granulomatous skin disorder of uncertain etiology. A number of clinical variants exist, most commonly localized annular plaques on the hands or feet, generalized lesions, or subcutaneous nodules in children. Histologically, GA exhibits granulomatous inflammation with either interstitial or palisading lymphocytes and histiocytes with mucin deposition.
Few data exist regarding the epidemiology of GA. Although the pathogenesis of GA is unknown, associations between GA and underlying systemic processes, such as diabetes mellitus, hyperlipidemia, thyroid disease, and human immunodeficiency virus (HIV), have been suggested.
The purpose of this retrospective study was to determine the number of cases of GA seen annually at the Department of Dermatology at the University of Pennsylvania (Philadelphia, Pennsylvania) from 2008 to 2014. Additionally, we reviewed all cases of biopsy-proven GA from 2010 to 2014 and reported the demographics, underlying medical comorbidities, medications, treatments, and outcomes seen in this patient population.
We identified the number of outpatients presenting with GA annually using PennSeek, a tool developed by the Penn Medicine Data Analytics Center to search electronic medical records (EMRs). We queried the EMR database to determine the number of discrete patients seen at the Department of Dermatology at the University of Pennsylvania annually from 2008 (the year the EMR was established) to 2014. We then used PennSeek to determine the number of patients given a diagnosis of GA annually from 2008 to 2014 based on the International Classification of Diseases, Ninth Revision (ICD-9).
After using PennSeek to identify all patients given the ICD-9 diagnosis of GA from 2008 to 2014, we reviewed the EMRs of these patients to identify cases that were biopsy proven. For the biopsy-proven cases of GA seen at the University of Pennsylvania from 2010 to 2014, we reviewed the EMRs of these patients for clinical characteristics and treatment outcomes. For each case, we recorded the patient’s age, sex, medical comorbidities, GA subtype, and medications.
This study was approved by the University of Pennsylvania’s institutional review board.