Granulomatous Dermatitis and Systemic Disease: An Association to Consider.

Granuloma annulare (GA) and interstitial granulomatous dermatitis (IGD) are granulomatous dermatoses with variable clinical appearances. GA is associated with diabetes mellitus, metabolic syndrome, chronic infections, and malignancies, while two Japanese reports described unusual cases of interstitial-type GA in setting of Sjogren syndrome. IGD was associated with rheumatoid arthritis, systemic lupus erythematosus, and autoantibodies. We report a case series of six patients with GA or IGD. Half of the patients were diagnosed with Sjogren syndrome, while all of them presented ANA positivity and the majority reported arthralgia. In many cases, GA showed interstitial-type histology, arising challenges in differential diagnosis with IGD. The overlap of clinical and histological features of GA and IGD can be explained considering them as a broad disease spectrum, including also the other forms of reactive granulomatous dermatitis. These conditions should be considered as an indicator of possible systemic disorders or other immunological dyscrasias, for which patients must be screened. Sjogren syndrome may be associated to GA also in Caucasians.