The terms “palisaded neutrophilic and granulomatous dermatitis,” “interstitial granulomatous dermatitis,” and the subset “interstitial granulomatous drug reaction” are a source of confusion. There exists substantial overlap among the entities with few strict distinguishing features. We review the literature and highlight areas of distinction and overlap, and propose a streamlined diagnostic workup for patients presenting with this cutaneous reaction pattern. Because the systemic disease associations and requisite workup are similar, and the etiopathogenesis is poorly understood but likely similar among these entities, we propose the simplified unifying term “reactive granulomatous dermatitis” to encompass these entities.
Key points
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Palisaded neutrophilic and granulomatous dermatitis, interstitial granulomatous dermatitis, and interstitial granulomatous drug reaction represent cutaneous reaction patterns that occur in the setting of a systemic trigger.
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Systemic triggers include connective tissue diseases (lupus, vasculitis, other), arthritides (rheumatoid arthritis, other inflammatory and reactive arthritides), malignancy (hematologic more often than solid organ), and medications.
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We suggest the unifying term “reactive granulomatous dermatitis” to encompass these entities, guide clinical management, and coordinate scientific literature regarding this group of reactive skin diseases.