Eosinophilic Arthritis

Criteria:

(1) clinical acute arthritis, which may be polyarticular

(2) eosinophilia in the aspirated fluid from an affected joint (either > 700 per µL or > 11% of the differential count)

Some patients may have:

(1) asthma

(2) urticarial skin rash

(3) eosinophilia in the peripheral blood

(4) Charcot-Leyden crystals in the joint fluid

Some patients have a probable explanation:

(1) parasitic infection (toxocariasis, filariais, other)

(2) allergic drug reaction

(3) allergic food reaction

(4) other allergic reactions

(5) hyperosinophilic syndrome

Some patients do not have a cause identified despite a complete and extensive workup.