"Every time I take marijuana, I seem to have allergy-type symptoms like sneezing and an itchy throat. Is there a way to avoid these symptoms so that I can continue to use marijuana for my condition?"
The answer is definitely yes, people can develop allergies to marijuana, just as they can develop an allergy to almost any plant. Although smoking marijuana can cause dry mouth, and the irritation of inhaling hot smoke can cause cough or raspy throat, itching in the throat and repeated sneezing does sound like a sign of allergy and is somewhat troubling because it implies the possibility of developing a more intense reaction. People can develop a skin rash from handling marijuana, not commonly as with poison ivy but occasionally, especially as an occupational illness. There has even been reported fatal anaphylaxis after ingestion of hemp seed by a patient allergic to marijuana, but most patients with allergies to marijuana will have symptoms like yours, and may also develop hives, wheezing, and other symptoms depending on how allergic they are, and other factors. And you should note that marijuana has known allergic cross-reactivity with some other common food plants such as tomato and hazelnut. If you are known to be allergic to any food I’d expect a greater chance of being allergic to marijuana. If you love using medical cannabis and want to go on using it it might be worth a trip to an allergist to better define what is going on. Although people can be desensitized to allergens like bee venom by slowly increasing doses, allergic sensitivity can also get worse with repeated challenges so I’d be cautious about cannabis use without further investigation.