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Allergic reaction due to drug or medication is very uncommon. Obviously a reaction caused of medicine or drug is a side effect.

These side effect or allergic reaction can range from a mild symptom like rashes to life-threatening reactions called as anaphylaxis. From our normal observation we come to know that skin is the very common organ involved in any of the above mild or life threatening reaction. It is not necessary that skin should or will be the organ involved in drug allergy reactions.

It is said that the allergic reaction to drug is seen or observed if the drug is consumed for the second time. Very rarely it is observed that the person gets an allergic reaction the time he takes the medication.

Drug Allergy causes

An allergic reaction is caused when the body’s immune system starts overreacting to the drug. This overreaction is called as hypersensitivity reaction. And also, not to forget that, Not all reactions to medication are due to an allergy.

• Some of the allergic reactions are caused because of the body’s inability to tolerate certain medication. Example antibiotics such as erythromycin causes gastric upset.
• Some of the allergic reactions are caused because of the body’s inability to bread down a medication. This case normally happens when the patient is having liver or kidney damage.
• Taking two type of medication at the same time may result into a high level of one drug. This drug may cause different side-effects and an allergic reaction to that drug will be observed. To explain this scenario consider a case were a patient takes erythromycin and theophylline at the same time. On consumption of the above drugs the level of theophylline increases to such an extent that it triggers siezure.
• The allergic reaction might occur if the body do not have enzyme responsible for metabolizing the drug. Though this possibility is very rare but cannot be neglected.

What are drug allergy symptoms?

The symptoms of any drug allergic reaction can be a mild reaction like rash to a sever life-threatening reaction. It is seen that people who are not allergic to any medicine sometimes show some symptoms like gastric upset, weakness,irritation etc.

During an allergic reaction the histamine level in the body increases and symptoms like hives, itchy skin, eye irritation, swelling of mouth, skin rashes are observed.

• Anaphylactic shock
• Eye reaction
  • conjunctivitis
• Gastrointestinal reactions
  • Diarrhea
  • Gastric upset
  • Heartburn
  • Nausea
  • Vomiting
• Mouth & nasal reactions
  • Hay fever
  • Itching mouth
  • Rhinitis
  • Nasal polyps
  • Sinusitis
  • Swollen lips
• Respiratory reaction
  • Asthma
  • Breathing problems
  • Cough
  • Wheezing
• Skin reaction
  • Angioedema
  • Atopic dermatitis
  • Blisters
  • Contact dermatitis
  • Photo-allergenic contact dermatitis
  • Flushing
  • Itching
  • Skin irritation
  • Urticaria
• Other reactions
  • Fever
  • Chest pain
  • Joint pain
  • Rapid pulse
  • Sweating

Drug allergy testing

• To confirm the drug allergy, it is important that some tests are performed to identify the drug allergy. There are different type of tests to diagnose drugs allergy.
• CAP-RAST is a blood test to identify allergy to drugs like antibiotics, cephalosporin, insulin, isphagula, penicillin, tetracycline.
• ELISA is another blood test to diagnose allergic reaction to drugs like erythromycin, insulin, penicillin, sulfamethoxazol, tetracycline.
• Skin patch test to diagnose allergic reaction to drugs like anaesthetics, antifungal drugs, antihistamines, antimitotic compound, benzocaine, cephalosporin, penicillin, neomycin, bacitracin.
• Skin photopatch test is used to identify the result of allergens on the skin on exposure of sunlight. The main symptom to be observed in this test is rashes.

Drug allergy treatment

The best treatment for drug allergies is avoidance.

• In case of occupational situations you need to take extra care of your self by using protective equipments like gloves, masks, improved ventilation equipments etc.
• While consuming any drug, read the label of the medicine before consuming. Check the expiry date of that medicine. An expired drug can cause a reverse action on your body. If you are having any diseases or allergies or other health conditions, please mention those to your doctor, this will help him to prescribe you the best suited medicine for your body.

There are neumourous medicines available in the market, and there are various medicines available to cure a particular disease or symptom. Following are some of the prescribed medication given for following symptoms:

• Anaphylactic shock: adrenaline, antihistamines, steroids.
• Diarrhoea: antidiarrhoeal drugs
• Gastric upset: painkillers
• Heartburn: antacids, alginates.
• Nausea: antihistamines
• Vomiting: anti-emetics
• Hay fever: antihistamines, cromoglycate, decongestants,nedocromil sodium, steroids, sympathomimetics
• Rhinitis: antihistamines, decongestants, immuntherapy
• Breathing problems: bronchodilators, corticosteroids
• Cough: antihistamines, bronchodilators, corticosteroids
• Skin irritation: emollients
• Urticaria: antihistamines, emollients, steroids