pGALS demonstrates small joint involvement in his fingers and nail pitting. There is a family history of psoriasis (father).
The diagnosis is Juvenile Psoriatic Arthritis (JPsA).
The involvement of small joints, often in an asymmetrical pattern, is typical of JPsA. The skin and nail changes may be absent or very mild. It is important to assess the nails in the hands and feet. Subtle skin changes may be found (scalp, natal cleft, umbilicus). The family history is helpful when the skin and nail changes are absent. It is important to assess all joints as it is not uncommon to detect joint involvement that is 'silent' - pGALS is useful to perform a quick screen of all joints.
There is risk of uveitis with JPsA and this is often without symptoms in the early stages (i.e no redness, pain or blurring).
The photograph below shows restricted full flexion of the left ring finger distal interphalangeal joint in a child with JPsA.