There appears to be a causal effect between inflammatory bowel disease (IBD) and psoriasis and psoriatic arthritis, according to a study published in JAMA Dermatology. Researchers examined the link between IBD and psoriasis or psoriatic arthritis in a bidirectional, two-sample, Mendelian randomization study using summary statistics from genome-wide association studies, which included up to 463,372 individuals. Total and direct effects were derived, and causal estimates were verified using a validation IBD sample, a series of Mendelian randomization methods, and sensitivity analyses. The samples included 12,882 IBD cases and 5,621 psoriasis cases. The risks for psoriasis and psoriatic arthritis were increased with genetically predicted IBD (pooled ORs, 1.10 and 1.10, respectively). Crohn’s disease sub-entity was linked with psoriasis and psoriatic arthritis (ORs, 1.16 and 1.13, respectively), while ulcerative colitis was not. No notable associations were identified in the reverse directions. “Raising awareness among clinicians and primary care physicians about the potential risk for psoriasis in patients with IBD will contribute to systematic diagnosis and interdisciplinary and early personalized treatment of patients,” the study authors wrote.