Introduction
Due to increase in the population that is having impaired immunity and also as there is an increasing pool of aged population because of the ever-lowering death rates, the incidence of allergies is on rise.

Definition
Drug allergy is an immunologically mediated reaction to a drug, which is quite different from its pharmacodynamic profile. It is entirely unrelated to its dosage. It is sometimes also called drug hypersensitivity.

Types
There are many different types of drug allergies but broadly there are two different types: a) Humoral
It is further subdivided into type I, type II and type III based on the type of cells involved.
b) Cellular

Diagnosis
Most commonly the signs and symptoms are redness, itching, rashes, swelling and runny nose. These symptoms occur from within few minutes to few hours. Whatever the symptoms, it is best to consult your doctor as soon as possible because these may be signs of a severe and even fatal reaction. One of the severe reactions is anaphylaxis. It is not necessary that if a person did not get allergy from a drug previously, he wont get it this time. Usually drugs from same group should not be taken if a reaction has occurred from a drug. The drugs most commonly implicated in drug allergies are penicillin, cephalosporins, sulfa drugs , anti convulsants, aspirin and insulin.

Management
a)Treatment
The first and foremost thing is to consult your doctor and if possible allergy specialist for he would be able to determine two things: first, the allergen and secondly the cause of the allergy. Finally when there has already been a reaction, then to treat this, there are certain medicines such as Elidel, Zyrtec, Flonase and Allegra.
Elidel helps in itching and rashes. It is a new and safe drug, which comes in a cream form.
Zyrtec is another safe drug. Because of its less likelihood of drowsiness as compared to the other members of its group, it has received good patient compliance. Besides being used for seasonal rhinitis it is also used for runny nose in drug allergy.
Flonase is another drug which although being steroidal is non-habit forming. It relieves the patients of stuffy nose because of congestion. It can also be used in children.
Allegra has similar use as zyrtec although it is even less sedating.
b)Prevention
It is best said that to manage in the best way any drug allergy is to stay away from the allergen that is the drug.

Further research
There are certain drugs such as xolair, which are still in their incipient stage, and not much of data is available

About the Author

Anju bala writes about Drug allergy topics.