About Drug Allergies
Not all patients react to medications in the same way. One person may develop a rash or other reactions when taking a particular type of medication, while another person on the same drug may have no adverse reaction at all.
While adverse reactions are somewhat common, only about 5% to 10% of these reactions are due to an actual allergy to the medication.
An allergic reaction occurs when the immune system overreacts to a harmless substance. In this case, it is the medication itself that triggers an allergic reaction. The body views the medication as a threat and begins producing histamines in response. This rise in histamine levels, in turn, causes the body to develop allergy symptoms.
Sensitivities vs Allergies
Some patients may have sensitivities to drugs, but these are not the same as allergies. “Sensitivities” to drugs may produce symptoms like those present in an allergic reaction; however, a reaction due to sensitivity to a medication does not involve the immune system.
Symptoms vs Allergies
Symptoms of drug allergies are also different from the common side effects one might expect when taking a medicine. For example, having an upset stomach is a common side effect associated with some painkillers. When a patient experiences one of these side effects, it does not mean that they are allergic or even necessarily sensitive to the drug. Drug toxicity, which occurs when an individual takes too much of a drug, is entirely different from a drug allergy.