PURPOSE: Observational studies have suggested a potential link between emotions and inflammatory dermatoses. However, research on the causal relationship between different types of emotions and inflammatory dermatoses is lacking. This study is aimed to investigate the causal relationship between negative emotions and inflammatory dermatoses through Mendelian randomization (MR) analysis. METHODS: Summary data of seven negative emotions were obtained from a genome-wide association study (GWAS) conducted by the MRC-IEU consortium. Seven inflammatory dermatoses including vitiligo, psoriasis, systemic lupus erythematosus, eczema, atopic dermatitis, acne, and rosacea were obtained from published GWAS. The MR analysis primarily employed the Inverse variance weighted (IVW) method, and supplemented by MR-Egger and other three MR methods. RESULTS: The IVW method revealed that guilty feelings have potential to increase the risk of psoriasis (OR = 1.02, 95% CI: 1.00-1.05, P = 0.019), while worrier/anxious feelings have a potential risk effect on eczema (OR = 1.07, 95% CI: 1.00-1.13, P = 0.042). Psoriasis could increase the occurrence of miserableness (OR = 1.41, 95% CI: 1.18-1.68, P = 0.0002), worrier/anxious feelings (OR = 1.26, 95% CI: 1.02-1.57, P = 0.033), nervous feelings (OR = 1.25, 95% CI: 1.05-1.49, P = 0.012), and loneliness/isolation (OR = 1.19, 95% CI: 1.04-1.36, P = 0.009). Eczema might cause an increased incidence of worrier/anxious feelings (OR = 1.038, 95% CI: 1.007-1.070, P = 0.014). CONCLUSION: This MR study revealed bidirectional causality between worrier/anxious feelings and eczema. It also found that guilty feelings may elevate the risk of psoriasis, and individuals with psoriasis may experience increased rates of miserableness, worrier/anxious feelings, nervous feelings, and loneliness/isolation.