A group of conditions having the characteristic elevation of eosinophils. These somewhat mysterious granulocytic leukocytes (white blood cells filled with cottage cheese) are definitely involved in parasite resistance, seem to initiate strong inflammation under some conditions, can facilitate clotting by inhibiting heparin, yet also are a part of the process of healing and inflammation control as an infection winds down. Eosinophilia is on one hand an inherited condition associated with atopic dermatitis (common, relatively benign, and irritating as hell), but, when acquired from chemical contact, drug reaction or spontaneously surfaced auto-immune response, it can destroy muscles, nerve, lungs, even kill. It caused the notorious string of chemical reactions that was triggered by tainted Japanese tryptophan.