Background: Interstitial granulomatous dermatitis (IGD) and palisaded neutrophilic granulomatous dermatitis (PNGD) are uncommon presentations of reactive granulomatous dermatitis. Histologic lesions characterized by IGD/PNGD patterns have been associated with systemic diseases, causing an unmet need for revealing clinical correlates. Objective: The aim of this study was to unravel the systemic diseases beyond dermatitis of IGD/PNGD. Methods: This study analyzed data from case studies, case series, and retrospective cohorts by searching PubMed, Embase, Web of Science, and the Cochrane Library, with no start date or language restrictions on Sep 4, 2021. Results: One hundred ninety-six publications were included (458 cases in total, 216 with details). Systemic diseases associated with IGD/PNGD were classified into 5 groups. Autoimmune disorders (n = 103, 47.6%) including rheumatoid arthritis (n = 51, 23.6%), systemic lupus erythematosus (n = 20, 9.3%), and others were the most common across all underlying diseases, followed by drug eruption (n = 52, 24.1%) such as tumor necrotic factor inhibitor reaction (n = 18, 8.3%) and malignancies (n = 27, 12.5%) such as hematologic malignancy (n = 20, 9.3%). The rest were infectious diseases (n = 12, 5.6%) and accidental conditions (n = 3, 1.4%). Conclusion: IGD/PNGD might be associated with autoimmune disorders, drug eruption, malignancies, infectious diseases, and accidental conditions. Patients with IGD/PNGD need further follow-up.