Description

A drug allergy is the immune system's reaction to a medicine. Any medicine over-the-counter, prescription or herbal — can trigger an allergy to medicines. However, a drug allergy is more likely with certain medications.

The most common symptoms of drug allergy are hives, rash, and fever. But an allergy to a medication can also cause severe reactions. This includes a serious life-threatening condition known as anaphylaxis.

A drug allergy is not the same as a drug side effects. A known side effect of the possible reaction to a medication. Side effects of the medications listed on their labels. An allergy to a medication, it is also different from the toxicity of the drugs. The drug toxicity is caused by an overdose of the medicine.

Symptoms

Symptoms of a serious drug allergy often occur within an hour after taking the drug. Other reactions, in particular, eruptions, one can spend hours, days, or weeks later.

Drug allergy symptoms may include:

  • Rash on the skin.
  • The hives.
  • The itching.
  • Fever.
  • The swelling.
  • Shortness of breath.
  • Wheezing.
  • Runny nose.
  • Itchy, watery eyes.

Anaphylaxis

Anaphylaxis is a rare, life-threatening allergy to a drug reaction that causes widespread changes in the way in which the systems of the body of the function. Symptoms of anaphylaxis include:

  • Narrowing of the airways and the throat, causing difficulty breathing.
  • Nausea or cramps in the belly.
  • Vomiting or diarrhea.
  • Dizziness or feeling light-headed.
  • Pulse weak and rapid.
  • Drop in blood pressure.
  • Seizures.
  • The loss of consciousness.

Other conditions resulting from allergies to medications

Least common drug allergy reactions to occur days or weeks after exposure to a medication and can last for some time after you stop taking the medicine. These include:

  • Serum sickness, which can cause fever, joint pain, rash, swelling, and nausea.
  • Drug-induced anemia, a reduction in the red blood cells, which can cause fatigue, irregular heartbeats, difficulty breathing and other symptoms.
  • Drug rash with eosinophilia and systemic symptoms, also called (DRESS), which results in a rash, a high white blood cell count, general swelling, inflammation of the lymph nodes, and infection of hepatitis, which returns after being idle.
  • Inflammation in the kidneys, also called nephritis, which may cause fever, blood in the urine, general swelling, confusion, and other symptoms.

When to see a doctor

Call 911 or emergency medical help if you experience signs of a serious reaction or suspected anaphylaxis after taking the drug.

If you have more mild symptoms of an allergy to a medication, consult a health care professional as soon as possible.

Causes

A drug allergy occurs when the immune system mistakenly identifies a drug as a harmful substance, such as a virus or a bacterium. Once the immune system detects a drug as a harmful substance, develops an antibody specific for that drug. This can happen the first time you take a medicine, but sometimes an allergy does not develop until there have been repeated exposures.

The next time you take the medicine, these antibodies specific for the flag of the medicine and direct attacks of the immune system in the substance. Chemicals released by this activity causes the symptoms associated with an allergic reaction.

You may not be aware of their first exposure to a medication, however. Some evidence suggests that trace amounts of a drug in the food supply, such as an antibiotic, may be sufficient for the immune system to create antibodies to it.

Some allergic reactions may be the result of a somewhat different process. The researchers believe that some medications can directly bind to a certain type of immune system white blood cell called the cell T. This event causes the release of chemicals that may produce an allergic reaction on the first time you take the medicine.

Drugs commonly associated with allergies

Despite the fact that any medicine can cause an allergic reaction, some drugs are more commonly associated with allergies. These include:

  • Antibiotics, such as penicillin.
  • Pain relievers, such as aspirin, ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve).
  • Chemotherapy drugs for the treatment of cancer.
  • Drugs for autoimmune diseases, such as rheumatoid arthritis.

Not drug reactions

Sometimes, a reaction to a medication can produce symptoms that are almost the same as that of a drug allergy. However, a reaction to a drug is not caused by the activity of the immune system. This condition is known as a hypersensitivity reaction is not allergic or pseudoallergic reaction to medications.

The medications that are most commonly associated with this condition include:

  • The aspirin.
  • Colouring agents used in imaging tests, known as radiocontrast media.
  • Opioids for the treatment of pain.
  • Local anesthetics.

Risk factors

While anyone can have an allergic reaction to a drug, some factors can increase someone's risk. These include:

  • A history of allergies, such as a food allergy or hay fever.
  • A personal or family history of drug allergy.
  • The increase of the exposure to a medication due to the high dose, the use of repeated or prolonged use.
  • Certain infections commonly associated with allergic reactions to medications, such as infection with HIV or Epstein-Barr virus infection.

Prevention

If you have an allergy to a drug, the best prevention is to avoid the use of the problem of the medicine. Steps you can take to protect yourself include the following:

  • Inform healthcare professionals. Make sure that your allergies to medicines is clearly identified in their medical records. Inform other healthcare professionals, such as your dentist or specialist physician.
  • Wear a bracelet. Wear a medical alert bracelet that identifies your allergies to medications. This information can ensure the adequate treatment in case of emergency.

Diagnosis

An accurate diagnosis is essential. Research has suggested that the consumption of drugs, allergies can be overdiagnosed and that patients may report allergies to medicines that have never been confirmed. Diagnosis of drug allergy can result in the use of less appropriate or more expensive drugs.

A health care professional normally performs a physical exam and asks him questions. The details about when symptoms begin, the time you took the medication, and the improvement or worsening of the symptoms are important clues to help your healthcare provider make a diagnosis.

Your health care professional may request additional tests or refer you to an allergy specialist, called an allergist for testing. These may include the following.

Skin test

With a skin test, the allergist or a nurse administers a small amount of a suspect of the medicine to the skin with a very small needle that touches the skin, a shot or a patch. A positive reaction to the test often causes redness, itching, lump.

A positive test result suggests that you may have a drug allergy.

A negative result is not so clear. For some drugs, a negative test result usually means that you are not allergic to the medicine. For other medicines, a negative result does not completely rule out the possibility of a drug allergy.

Blood tests

A health professional may order blood tests to rule out other conditions that could be causing the symptoms.

While there are blood tests for the detection of allergic reactions to certain medications, these tests are not often used due to the limited research regarding its accuracy. They can be used if there are concerns about a serious reaction to a skin test.

The results of the diagnostic evaluation

After looking at your symptoms and the results of the test, a healthcare provider can usually get to one of the following conclusions:

  • You have a drug allergy.
  • You do not have a drug allergy.
  • You may have a drug allergy — with varying degrees of certainty.

These findings may help future treatment decisions.

Treatment

Treatments for allergies to medicines can be divided into two general strategies:

  • Treatment for presenting symptoms of the allergy.
  • The treatment that can allow you to take an allergy-causing medication if medically necessary.

The treatment of the current symptoms

The following treatments may be used to treat an allergic reaction to a medicine:

  • The suspension of the drug. If a healthcare provider determines that you have an allergy to medicines or likely allergy — stopping the drug is the first step in the treatment. For many people, this may be the only intervention needed.
  • Antihistamines. Your health care professional may prescribe an antihistamine or to recommend an antihistamine over-the-counter, such as diphenhydramine (Benadryl). An antihistamine can block the immune system chemicals activated during an allergic reaction.
  • Corticosteroids. Corticosteroids administered as an injection or by mouth can be used to treat the symptoms associated with more severe reactions.
  • The treatment of anaphylaxis. Anaphylaxis requires an immediate injection of epinephrine. The in-Hospital care is also necessary to maintain the blood pressure and breathing.

Taking the allergy-causing drugs

If you have a confirmed allergy to a medicine, a health professional is likely that you do not prescribe the drug that causes a reaction unless it is necessary. Sometimes — if the diagnosis of allergy to drugs is uncertain or there is no other treatment — your health professional may use one of two strategies to give you the suspicion of the medicine.

With the strategy, your health care professional provides a careful supervision. Supportive care is also available in the case of an adverse reaction. These treatments are generally not used if drugs that have caused serious, life-threatening reactions in the past.

Ranked challenge

If the diagnosis of a drug allergy is uncertain and a professional of the health to the judges that the allergy is rare, a graduate of the drug challenge may be an option. With this procedure, you receive 2 to 5 doses of the medicine, starting with a small dose and increase the dose desired, also called the therapeutic dose.

If you arrive at the therapeutic dose with no reaction, then your health care professional may recommend that you take the prescribed medication.

Drug desensitization

If it is necessary for you to take a drug that has caused an allergic reaction, your health care professional may recommend a treatment called drug desensitization. With this treatment, you get a very small dose and then increasing dose every 15 to 30 minutes over several hours or days. If you can reach the desired dose with no reaction, then you can continue with the treatment.

Preparing for your appointment

Consult a health care professional if you have symptoms that may be related to a drug that has recently begun to take or take on a regular basis. Be prepared to answer the following questions. These details are important to help determine the cause of your symptoms.

  • What symptoms have you had? Don't let the details, even if they don't seem related.
  • When did the symptoms begin? Be as specific as possible.
  • How long do the symptoms last?
  • What's new in the medicine have you taken?
  • When do you take it?
  • Has stopped taking the medication again?
  • What other drugs without a prescription or prescription drugs you take?
  • What herbal medicines, vitamins and diet supplements do you take?
  • At what time of day you take your other medications or supplements?
  • Has increased the dose of any other drug or supplement?
  • You stopped taking your regular medications or supplements?
  • Did nothing to treat their symptoms, and if so, what was the effect?
  • You have had a reaction to a medication in the past? If so, what the medicine was for?
  • Do you have hay fever, food allergies or other allergies?
  • Is there a history of drug allergies in your family?

You may want to take photographs of any condition, such as a rash or swelling, to show your health care team. These can help if the symptoms have subsided for the time of your appointment.

Symptoms and treatment of Drug allergy