Idiopathic anaphylaxis has the same symptoms as anaphylaxis, but has no obvious trigger and yields no antibodies to a benign substance. However, histamines and other chemicals that can interrupt life- sustaining body functions are released.
Symptoms can include hives, sneezing, coughing, itching, runny nose, "pins and needles" sensation of the skin, dizziness, nausea, vomiting, diarrhoea, abdominal pain, loss of consciousness, flushing, facial oedema, swelling of mouth and throat, urticaria, anxiety, respiratory difficulties and hypotension, which may progress to shock and collapse. Cardiovascular collapse can occur without respiratory symptoms. Early recognition and treatment of anaphylaxis is vital. If hives and facial redness are the only symptoms, and attacks are rare, the disease can be cured with hormone injections.
About 47,000 Americans suffer from idiopathic anaphylaxis. Attacks may occur once a year or 5 times a day. Many cases are misdiagnosed as asthma or unspecified food allergies, which puts the patient's life at risk, since he could die of an anaphylactic attack.