We present one of the largest PG case series to date. In our study, we found that biopsy of a PG lesion rarely yielded characteristic features of the disease and tissue pathology should not be used to exclude a PG diagnosis. We also found a female predominance and associations with IBD and haematological disorders. Patients with PG in this series had high rates of depression and hepatitis. Further work is needed to establish the mechanism(s) underlying these findings.

We found that patients with both, psoriasis and IBD have a number of further associated comorbidities, some at significantly higher levels than individuals with psoriasis-only. Common inflammatory pathways and genetic predispositions for specific patterns in the immune response may play an important role in the evolution of associated conditions.