Juvenile onset psoriatic arthritis in a patient with X‐linked agammaglobulinemia (Bruton's disease)

We describe a 47‐year‐old male patient suffering from X‐linked (or Bruton's) agammaglobulinemia with severe psoriatic arthritis (PsA), which started in childhood. PsA has been previously described in T‐cell defective disorders, such as HIV infection, but our observation demonstrates that this rheumatic disease can also occur in subjects with B‐lymphocyte cell functional impairment. Chronic inflammatory (bacterial?) involvement of the bowel could represent a pathogenetic connection between X‐linked agammaglobulinemia and PsA.