Behçet’s disease (BD) is a complex, recurring inflammatory disorder with autoinflammatory and autoimmune components. This comprehensive review aims to explore BD’s pathogenesis, focusing on established genetic factors. Studies reveal that HLA-B*51 is the primary genetic risk factor, but non-HLA genes (ERAP1, IL-10, IL23R/IL-12RB2), as well as innate immunity genes (FUT2, MICA, TLRs), also contribute. Genome-wide studies emphasize the significance of ERAP1 and HLA-I epistasis. These variants influence antigen presentation, enzymatic activity, and HLA-I peptidomes, potentially leading to distinct autoimmune responses. We conducted a systematic review of the literature to identify studies exploring the association between HLA-B*51 and BD and further highlighted the roles of innate and adaptive immunity in BD. Dysregulations in Th1/Th2 and Th17/Th1 ratios, heightened clonal cytotoxic (CD8+) T cells, and reduced T regulatory cells characterize BD’s complex immune responses. Various immune cell types (neutrophils, γδ T cells, natural killer cells) further contribute by releasing cytokines (IL-17, IL-8, GM-CSF) that enhance neutrophil activation and mediate interactions between innate and adaptive immunity. In summary, this review advances our understanding of BD pathogenesis while acknowledging the research limitations. Further exploration of genetic interactions, immune dysregulation, and immune cell roles is crucial. Future studies may unveil novel diagnostic and therapeutic strategies, offering improved management for this complex disease.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is the virus responsible for coronavirus disease 2019 (COVID‐19), which manifests as a flu‐like respiratory infection affecting multiple organ systems, including the gastrointestinal system, central nervous system, cardiovascular system, skin, and mucosa. In this review, we investigated the literature on specific manifestations of COVID‐19 in the oral mucosa. An online literature search in PubMed, Scopus, Google Scholar, and Medline was conducted to retrieve relevant studies on confirmed COVID‐19 patients with oral mucosa findings published between December 31, 2019, and April 07, 2021. After an independent review by two authors, 39 articles considering 59 laboratory‐confirmed cases of SARS‐CoV‐2 infection were included in the final analysis. The most common finding, reported in 29 patients (43.9%), was Kawasaki‐like syndrome. In addition, oral ulcers including aphthous, hemorrhagic, and necrotic ulcers were reported in 24 patients (36.3%). Other lesions reported included pustules, macules, bullae, maculopapular enanthema, and erythema multiforme‐like lesions. Concomitant skin lesions were present in 60.6% of patients. Fever was reported in 86.2% of patients. Forty‐eight patients (76.1%) were hospitalized. Loss of taste and smell was present in 30.8% of the patients. A comprehensive understanding of the dermatologic manifestations of COVID‐19 can improve and facilitate patient management and referrals.