Because there is an increased risk that you may experience an anaphylactic shock (also called anaphylaxis) if you suffer a massive degranulation, you will need to take some precautions to be able to handle such an event. You will need to carry with you a self-injectable dose of epinephrine at all times. This dose is contained in a syringe called an EpiPen. That may sound a bit sinister, but it shouldn't be that big a deal. It just means you will have to get into the habit of reaching for your EpiPen as you reach for your door keys and not to leave home without it.
Once you have been diagnosed with Mastocytosis, your doctor will prescribe either one or two EpiPens. An EpiPen is essentially a very sturdy syringe that contains a shot of 0.3 ml of epinephrine. Because of the protective sheath and delivery mechanism around the syringe, you will need to familiarise yourself with the instructions to administer the shot should you need it. Your doctor or your nurse will spend 10-20 minutes with you to teach you how to do this safely and answer any queries you may have. Again, there is nothing to worry about, it is a very simple procedure once you know how to do it. However, you must inject yourself using the correct procedure.
It is a good idea to take a family member or a close friend with you when you are taught the EpiPen administration procedure. This will ensure that someone close to you will know how to administer the shot should you be unable to do so yourself for any reason. It would be sensible as well to teach several of your family members how to perform the procedure.
The epinephrine in the EpiPen is used to treat the symptoms of anaphylactic reactions in emergency situations. It has to be administered as soon as symptoms of allergic reactions develop. This could happen within minutes of being exposed to an allergen. Your doctor will advise you of the allergic signs and symptoms to look out for. It is quite likely you'll know whether to use the EpiPen based on your symptoms. You can also find information on the symptoms to look out for in the Anaphylaxis post. There is also a worthwhile video to watch here.
The important thing is not to panic and to inject yourself without asking too many questions. Also, don't worry you'll forget the instructions. For one, the instructions are quite simple, and furthermore they are repeated on the package of the EpiPen. Check out the video below to reassure yourself that you can do it.
Here's an interesting video showing that you actually need very little pressure to activate the EpiPen. This is important to know, as you could easily eject the needle without realising it.