In 1990, the U.S. Food and Drug Administration (FDA) temporarily pulled all L - tryptophan products off the market after more than 1,500 people who took L - tryptophan supplements developed a blood disorder
called eosinophilia myalgia syndrome.
In 1989, more than 1500 people around the world
contracted eosinophilia malgia syndrome (EMS), a rare blood disease that causes tissue damage similar to burns, and sometimes death.
One more thing is important, investigating food, medication, and other allergies in patients with high IgE or
eosinophilia in GI biopsies.
A drug trial using a common dose of the serotonin antagonist cyproheptadine did not reduce
airway eosinophilia (abnormally high amounts of eosinophils are found in asthma patients) compared with placebo; although overall airway hyperreactivity was not significantly reduced with treatment, individual cats (2 of 6) did have decreased airway hyperresponsiveness or less of an allergic response.
Other dogs may have PIE, pulmonary infiltration
with eosinophilia, an allergic reaction in the lungs.
Tryptophan may also increase your risk for a condition called
eosinophilia - myalgia syndrome, especially if you have liver or kidney disease or a condition called eosinophilia.
Side effects of Methimazole (Tapazole / Felimazole) are common and include anorexia, vomiting, lethargy, excoriations, bleeding, hepatopathy, thrombocytopenia, agranulocystois, leukopenia,
eosinophilia, lymphocytosis, positive ANA, and positive direct antiglobulin test.
Hypersensitivity reactions unrelated to dose can occur with these agents and can be manifested as rashes, fever,
eosinophilia, neutropenia, agranulocytosis, thrombocytopenia, leukopenia, anemias, lymphadenopathy or full blown anaphylaxis.
In that case bloodwork might show increased numbers of eosinophils in your pet's circulation (
eosinophilia), adding to suspicion that EGC is the underlying cause of your pet's skin condition (however, many cats with EGC, have no increase in their blood eosinophil numbers).