The skin (dry itchy skin, psoriasis, eczema, contact-dermatitis), joints, and eyes (uveitis) are the favorite targets of our immune system with extra-intestinal-manifestations (EIMs). Heard a number of people here over the years complain about
them, as the incidence is about
20-25% of us who encounter EIMs.
A good read on the joint pains/inflammation (known as arthritis which can hit us at any age):
https://www.crohnscolitisfoundation.org/sites/default/files/legacy/assets/pdfs/emr/arthritiscomplications.pdf