Hi, Im a 57, 130 lb 19 year old girl who recently had my 5th encounter (on saturday) of going unconscious unexpectedly and for 5-6 minutes.  It was around 3 in the afternoon, I was not dehydrated and had already eaten lunch.  I have a long list of allergies; the most dangerous are shellfish and  penicillin.  Every time I come back to consciousness I have large red blotches and hive on my arms and upper thighs.  Previous Doctors have thought my fainting spells were caused my anaphylactic allergic reactions but recently another doctor claimed I have vasodepressor syncope and the hives are caused from over-heating (which I often get hives from).  I was wondering If you also thought I should see a cardiologist or should continue on new allergy medications.
Howell come to ChatDoctorI really appreciate your concern, apart from the allergic condition if this is pure syncope then this could be due to cardio vascular disease or central nervous system related disease and these both possibilities need to be ruled out, if this turned unremarkable then one can think about the allergy, but syncope is very uncommon in your case, with eruption of haves hysteric attack may be likely, hope this information helps.