Epigenetics has been discussed as a potential factor influencing the pathophysiology and severity of inflammatory skin diseases. In recent years, emerging evidence suggests that epigenetic mechanisms are involved in the pathophysiology of not only atopic dermatitis (AD) and psoriasis (PSO) but also lupus erythematosus and oral lichen. A systematic review of the literature was undertaken to provide an unbiased and comprehensive update on the involvement of methylation patterns in inflammatory skin disease. In addition to reviewing the contribution of epigenetic mechanisms regulating the development of inflammatory skin diseases, this review aimed to discern the overlap of epigenetic risk factors of the 2 most common inflammatory skin diseases, AD and PSO. Although AD and PSO are both inflammatory skin diseases, both show a distinct genetic profile. Herein, we give evidence that both AD and PSO share epigenetic risk factors that might contribute to disease characteristics. We identify a core subset of inflammation-associated differentially methylated genes in both AD and PSO and discuss the association in other inflammatory diseases.