Background:

Granuloma Annulare is often referred to GA for short. “Granuloma” refers to a special type of inflammation in the skin that produces this condition. “Annulare” refers to the round arcing shape with central clearing that is also typical of the condition. It presents with smooth ring-like raised plaques that slowly develop on the skin and may expand over time. It is considered a benign and self-limited condition, although it may come and go for many years. There are multiple subtypes including localized, generalized, subcutaneous, patch, and linear.

Causes and Associations:

The exact etiology is unknown. There may be some underlying genetic susceptibility. No infectious cause has been identified. Patients with the GA do have a higher incidence of dyslipidemia particularly with the generalized form. Generalized GA may also be associated with diabetes. Historically, it has been thought there could be an increased risk of malignancy including lymphoma in patients with GA however a definitive relationship has not been confirmed.

Diagnosis and Screening:

The diagnosis can often be made based on the classic clinical appearance. However, a biopsy can be helpful to confirm atypical presentations or rule out similar entities in the differential such as Interstitial granulomatous dermatitis (IGD), Sarcoid, Erythema Annulare Centrifugum (EAC), or others. The histology generally shows palisading histiocytes around necrobiosis with increased mucin. A scraping of skin cells for potassium hydroxide (KOH) evaluation is helpful to exclude fungus (tinea) if any scaling is present.

Screening for associated disorders may be justified. Consideration can be given to performing a lipid profile and screening for diabetes particularly if any additional symptoms are present. For older patients or atypical presentations we always recommend patients are up to date on age appropriate cancer screenings.

Treatment:

For localized mild cases treatment is not always required and may spontaneously resolve after a few years. The most common first-line treatment are potent topical steroids or steroids injected directly into the lesions (intralesional steroid injections). These treatments are considered safe but potential side effects include thinning skin and stretch marks with excessive use. Additional treatments can include topical calcinuerin inhibitors, ultraviolet light. Systemic therapies such as plaquenil are sometimes indicated if refractory to first-line therapies.