Noninfectious granulomatous dermatitides: a review of 8 disorders (Part 1 of 3).

In this review we focus on 2 of the noninfectious granulomatous dermatitides, granuloma annulare and interstitial granulomatous dermatitis (the remaining 6 will be discussed in Parts 2 and 3), with an overview of their clinical and histological presentations, differential diagnoses, and treatment options. The disorders we discuss are polymorphic in their clinical and histopathological presentations, follow chronic or undulating disease courses, and are typically recalcitrant to therapeutic interventions. Although the clinical history may be helpful, careful and thorough histopathological examination is required. Established treatment algorithms for these disorders are lacking, and no randomized, placebo-controlled studies have been published. Future investigations should focus on the evaluation of larger cohorts, not only to establish treatment recommendations in randomized, placebo-controlled trials, but also to reach a greater understanding of disease pathogenesis and clinical-pathological presentation.