Reactive Granulomatous Dermatitis (Interstitial Granulomatous Dermatitis, Palisaded Neutrophilic and Granulomatous Dermatitis, and Variants)

Reactive granulomatous dermatitis: A useful and encompassing term

“…1 , 2 Similarly, the definition of IGD has evolved, with an initial description of an asymptomatic, firm, palpable, linear band on the upper portion of the trunk with histopathologic changes of variable interstitial histiocytes often surrounding areas of abnormal collagen producing the characteristic “clefting” and “floating sign” in patients with inflammatory arthritis. 1 , 3 However, these classic subcutaneous cords may be present in <10% of cases. 1 , 3 , 4 Other presentations include symmetric erythematous/violaceous patches or plaques on the proximal aspects of the trunk and limbs, skin-colored papules, annular plaques, subcutaneous nodules, and papules on the elbow (classically, a sign of PNGD).…”

“…1 , 3 However, these classic subcutaneous cords may be present in <10% of cases. 1 , 3 , 4 Other presentations include symmetric erythematous/violaceous patches or plaques on the proximal aspects of the trunk and limbs, skin-colored papules, annular plaques, subcutaneous nodules, and papules on the elbow (classically, a sign of PNGD). 1 , 3 …”

“…PNGD is reported most often in the setting of lupus and connective tissue diseases but may occur in inflammatory arthritis, lymphoproliferative disease, and other inflammatory settings. 1 , 3 IGD now includes associations with connective tissue diseases, including lupus, lymphoproliferative diseases, and other inflammatory disease states. 1 , 3 …”

“…1 , 3 IGD now includes associations with connective tissue diseases, including lupus, lymphoproliferative diseases, and other inflammatory disease states. 1 , 3 …”

“…This terminology has already been used in various circumstances by dermatologists and dermatopathologists. 1 , 3 , 4 Although RGD may represent a spectrum, with patients with PNGD-like RGD, IGD-like RGD, or even polycyclic or granuloma annulare–like RGD (RGD differing from classic granuloma annulare by histology, specifically the lack of increased mucin levels), 3 the overarching term is a helpful concept for clinicians and pathologists to guide appropriate evaluation for systemic disease and search for potential triggers. Patients presenting with any of these 3 entities require similar systemic evaluation, medical history review, probing regarding medications, and evaluation for potential triggers ( Table Ⅰ ).…”