Granuloma Annulare: A Retrospective Series of 133 Patients
Although granuloma annulare (GA) is a relatively common dermatologic condition, little is known about its epidemiology and pathogenesis. Additionally, there is conflicting evidence regarding its association with other diseases. In our retrospective study, we attempted to determine the number of cases of GA seen annually at a large academic center and clarify disease associations with GA. We utilized PennSeek, a tool developed by the Penn Medicine Data Analytics Center to search electronic medical records (EMRs), to identify all cases of GA seen at the University of Pennsylvania (Philadelphia, Pennsylvania) from 2008 to 2014. All biopsy-proven cases of GA from 2010 to 2014 were reviewed for medical comorbidities, medications, treatments, and outcomes. On average, the percentage of patients given a diagnosis of GA annually was 0.22%. There were 133 cases of biopsy-proven GA that were reviewed. The findings solidify our understanding of the epidemiology of GA and diseases that can be associated with GA.
Practice Points
- Although the pathogenesis of granuloma annulare (GA) is unknown, associations between the disorder and underlying systemic processes (eg, diabetes mellitus, hyperlipidemia, thyroid disease, human immunodeficiency virus) have been proposed.
- This study elicited a period prevalence of GA of 0.22% to 0.27%.
- The most commonly used treatments of GA were topical steroids and intralesional triamcinolone, followed by hydroxychloroquine.
Results
On average, the percentage of patients given a diagnosis of GA annually was 0.22% (95% CI, 0.19%-0.24%). A Pearson χ2 test was used to determine if any single annual percentage was significantly different from the others. We found a P value of .321, which suggests that the percentage of patients with GA seen annually has been stable from 2008 to 2014 (Figure).
There were 133 cases of biopsy-proven GA that were reviewed for clinical characteristics; of them, 86.5% were female. Thyroid disease was noted in 30.1% of patients, hyperlipidemia in 30.1%, and hematologic malignancies in 3.8%. Type 1 diabetes mellitus was noted in 1.5% of patients. None of the patients were HIV-positive, 1.5% were hepatitis B–positive, and 2.3% were hepatitis C–positive. Of the 133 cases, 64.7% had localized GA and 30.8% had generalized GA. Photosensitive and papular GA were rarer (1.5% and 2.3% of cases, respectively). Use of a selective serotonin reuptake inhibitor (SSRI) was noted in 18.1% of patients; use of a calcium channel blocker was noted in 9.0% (Table 1).
The most commonly prescribed treatment of GA was topical steroids; 30.9% of patients who were prescribed a topical steroid experienced improvement of their condition. Intralesional triamcinolone was the second most prescribed treatment of GA, with an improvement rate of 40.0% (Table 2).
Comment
We attempted to determine the period of prevalence of GA in a tertiary care, university-based referral practice and evaluate disease associations, treatments, and outcomes of patients with biopsy-proven GA. Our calculated period prevalence of GA of 0.22% to 0.27% is consistent with another review, which reported that 0.1% to 0.4% of new patients presenting to a dermatology practice were given a diagnosis of GA.1 More than 85% of the cases we reviewed were seen in females, a finding that is more heavily skewed compared to prior reports that have suggested a female to male ratio of approximately 1:1 to 2:1.1-7 Our findings suggest that GA is a female-predominant condition, or women may be more likely to seek evaluation for the condition.
More than 95% of the cases we reviewed were localized (64.7%) or generalized (30.8%) GA, making these variants the most common forms of GA, which is consistent with prior reports.1-3,8,9 Other varieties of GA—drug induced, patch, perforating, photosensitive, palmar, and papular—appear rare. Because this study was conducted at an adult hospital, subcutaneous GA, which often is seen in children, may be underrepresented. As a retrospective chart review, it is possible that documentation is insufficient to capture each rare variant.
