Allergic reactions tend to worsen over time, getting more severe with each occurrence. Severe allergic reactions can be life-threatening reactions. Allergies to certain medications such as antibiotics or even aspirin can be very dangerous as well as allergies to natural rubber latex. If you have experienced an intense allergic reaction you should be tested to determine the cause and the severity of the allergy. Allergy blood tests are the most convenient testing available providing reliable and easy to understand results.