You may experience side effects to the drugs you have to take, but serious allergic reactions to medication are rare.
It is not always easy to distinguish an allergic reaction from a recognized side effect.
If you have a bad reaction to a medicine, it is important to tell your doctor so that it goes down on your medical records.
You may forget your adverse reaction, but your body's immune system has a good memory that will last for years.
You are more likely to develop an allergy to a drug you take occasionally and to one that is injected than to one you swallow regularly.
Aspirin and other non steroidal anti inflammatory drugs can bring on an asthma attach in around two to four percent of asthmatics, particularly middle aged women.
Symptoms of such an aspirin induced attack may include a rash, flushing and a runny nose as well as a narrowing of the airways.
These everyday drugs, along with the food additives terrain and benzoic acid, hamper the production of substances called prostaglandins.
They are found all over the body and are involved in pain perception and so an effective painkiller will act on them to stop their production.
But prostaglandins also affect the airways, some relaxing them and others constricting them.
In an asthmatic person, aspirin and inflammatory drugs can upset the delicate balance of airways that are already inflamed, triggering an attack.
Antibiotics, such as amoxicillin and trimethoprim are the main offenders, can produce a nasty rash.
It is unlikely that you will be allergic to all antibiotics, so your doctor will make a note of the ones that cause a reaction and ensure that you are give a different one next time.