Allergy to penicillin

Description

Penicillin allergy is an abnormal reaction of the immune system to the antibiotic drug penicillin. Penicillin is prescribed for the treatment of various bacterial infections.

Common signs and symptoms of penicillin allergy include hives, rash and itching. Severe reactions include anaphylaxis, a potentially life-threatening condition that affects multiple systems of the body.

Research has shown that penicillin allergies may be over-reported — a problem that may result in the use of less appropriate and more expensive treatments with antibiotics. Therefore, an accurate diagnosis is necessary when penicillin allergy is suspected to ensure the best treatment options in the future.

Other antibiotics, particularly those with chemical properties similar to penicillin, may also cause allergic reactions.

Symptoms

The signs and symptoms of penicillin allergy often occur within an hour after taking the drug. Less commonly, reactions can occur hours, days, or weeks later.

Penicillin allergy signs and symptoms may include:

  • Skin rash
  • The hives
  • Itching
  • Fever
  • Swelling
  • Shortness of breath
  • Wheezing
  • Runny nose
  • Itching, watery eyes
  • Anaphylaxis

Anaphylaxis

Anaphylaxis is a rare life-threatening allergic reaction that causes the dysfunction of generalized systems of the body. The signs and symptoms of anaphylaxis include:

  • Narrowing of the airways and the throat, causing difficulty breathing
  • Nausea or abdominal cramps
  • Vomiting or diarrhea
  • Dizziness or lightheadedness
  • Weak, rapid pulse
  • Drop in blood pressure
  • Seizures
  • Loss of consciousness

Reactions resulting from penicillin allergy

Least common penicillin allergy reactions occur days or weeks after exposure to the drug and may persist for some time after you stop taking it. These conditions 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, shortness of breath, and other signs and symptoms
  • Drug reaction with eosinophilia and systemic symptoms (DRESS), which results in a rash, a high white blood cell count, general swelling, inflammation of the lymph nodes and recurrence of latent infection of hepatitis
  • Stevens-Johnson syndrome or toxic epidermal necrolysis, which consists of blisters and peeling of the skin
  • Inflammation in the kidneys (nephritis), which may cause fever, blood in the urine, general swelling, confusion, and other signs and symptoms

Adverse events which are no allergic reactions

You may experience side effects of penicillin — as with other drugs — which are not an allergic reaction to the drug. Depending on the type of penicillin, the common side effects may include nausea or diarrhoea, headache, vaginal itching or. Signs or symptoms of an infection for which you are being treated — or unrelated symptoms — it can also be understood as a reaction reaction to medications.

When to see a doctor

See your doctor as soon as possible if you experience signs or symptoms of allergy to penicillin. It is important to understand and discuss what is an allergic reaction, which is a typical side effect and what you can tolerate in the taking of a medication.

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

Causes

Penicillin allergy occurs when the immune system becomes hypersensitive to the drug — mistakenly react to the drug as a harmful substance, as if it were a viral or bacterial infection.

Before the immune system can become sensitive to penicillin, you have to be exposed to the medication, at least once. If and when your immune system mistakenly identifies the penicillin as a harmful substance, it develops an antibody to the drug.

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

Prior exposure to penicillin may not be obvious. Some evidence suggests that trace amounts of it in the food supply may be sufficient for a person's immune system to create an antibody to it.

Penicillins and related drugs

Penicillins belong to a class of antibacterial drugs beta-lactam antibiotics. Although the mechanisms of the drugs varies, usually they fight infections by attacking the walls of the bacterial cells. In addition to penicillins, other beta-lactam antibiotics are most commonly associated with allergic reactions are a group called cephalosporins.

If you have had an allergic reaction to one type of penicillin, it can be — but not necessarily — allergic to other types of penicillin or cephalosporins.

Penicillins are:

  • Amoxicillin
  • Ampicillin
  • Dicloxacillin
  • Nafcillin
  • Oxacillin
  • Penicillin G
  • Penicillin V
  • Piperacillin
  • Ticarcillin

Cephalosporins are:

  • Cefaclor
  • Cefadroxil
  • Cefazolin
  • Cefdinir
  • Cefepime (Maxipine)
  • Cefotetan
  • Cefprozil
  • Cefuroxime
  • Cephalexin (Keflex)

Risk factors

While anyone can have an allergic reaction to penicillin, some factors can increase your risk. These include:

  • A history of allergies such as food allergy or hay fever
  • Allergic reaction to another medication
  • A family history of drug allergy
  • The increased exposure to penicillin, due to the high dose, the use of repetitive or prolonged use
  • Certain diseases commonly associated with allergic reactions to medications, such as infection with human immunodeficiency virus (HIV) or the Epstein-Barr virus

Prevention

If you have an allergy to penicillin, the most simple is to avoid the consumption of drugs. Steps you can take to protect yourself include the following:

  • Inform the health care workers. Make sure that your allergy to penicillin or other antibiotics allergy 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.

Allergy to penicillin

Diagnosis

A thorough exam and appropriate diagnostic tests are essential for an accurate diagnosis. A misdiagnosed penicillin allergy may result in the use of less appropriate or more expensive antibiotics.

Your doctor will perform a physical examination, ask questions about your symptoms, and order additional tests. You may be referred to an allergy specialist (allergist) for these tests. These may include the following.

Skin tests

With a skin test, the allergist or nurse administers a small amount of the suspected penicillin to your skin with a very small needle. A positive reaction to the test cause redness, itching, lump.

A positive result indicates a high likelihood of penicillin allergy. A negative test result usually means that you're not at high risk of allergy to penicillin. But a negative result is more difficult to interpret because some types of drug reactions may not be detected by skin tests.

Ranked challenge

If the diagnosis of an allergy to penicillin is uncertain, a graduate of the drug challenge may be recommended. With this procedure, you can receive up to five doses of the suspected penicillin, starting with a small dose and increase the dose desired. If you arrive at the therapeutic dose with no reaction, then your doctor to the conclusion that you are not allergic to that type of penicillin. You will be able to take the medication prescribed.

If you are allergic to one type of penicillin, your doctor may recommend a gradual challenge with a type of penicillin or cephalosporin that is less likely — because of the known chemical properties — to cause an allergic reaction. This will allow your doctor to identify an antibiotic that can be used with safety.

During a drug challenge, your doctor provides you with careful monitoring and supportive care services are available for the treatment of an adverse reaction.

Treatment

Interventions for a penicillin allergy can be divided into two general strategies:

  • The treatment for the current symptoms of the allergy
  • Desensitization to penicillin

The treatment of the current symptoms

The following interventions can be used to treat the symptoms of an allergic reaction to penicillin:

  • The withdrawal of the drug. If your doctor determines that you have an allergy to penicillin or likely allergy — the suspension of the drug is the first step in the treatment.
  • Antihistamines. Your doctor may prescribe an antihistamine or recommend an over-the-counter antihistamines such as diphenhydramine (Benadryl), which can block the immune system chemicals activated during an allergic reaction.
  • Corticosteroids. Whether oral or injected corticosteroids may be used to treat the inflammation associated with more severe reactions.
  • The treatment of anaphylaxis. Anaphylaxis requires an immediate injection of epinephrine, as well as hospital care to maintain blood pressure and breathing.

Drug desensitization

If there is no other antibiotic treatment options available, the doctor may recommend a treatment called drug desensitization that can allow you to take a course of penicillin for the treatment of an infection. With this treatment, you get a very small dose and then gradually increased the dose every 15 to 30 minutes over the course of several hours or a few days. If you can reach the desired dose with no reaction, then you can continue with the treatment.

It is important to take the medication as directed to maintain its tolerance over the entire course of treatment. If you need to penicillin in the future, it will be necessary to repeat the desensitization treatment.

You are carefully monitored during the intervention, and supportive care is available for the treatment of reactions. The desensitization is not always with success, and there is a risk of severe reactions.

Preparing for your appointment

Be prepared to answer the following questions. These details will be important to help your doctor determine the cause of your symptoms.

  • What symptoms have you had?
  • What is the name of the penicillin or another antibiotic I was taking?
  • Why was prescribed the medication?
  • Have you had these symptoms in the past, when not to take this medicine?
  • How long after taking penicillin did the symptoms begin?
  • How long do the symptoms last?
  • You've stopped taking the medication?
  • What other drugs, herbal medications, 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?
  • Have stopped taking their medications, or supplements?
  • Did nothing to treat their symptoms, and what was the effect?
  • You have had a reaction to any drug in the past? If so, what drug was it?
  • Do you have hay fever, food allergy or other allergies?
  • There is a history of penicillin or other drug allergies in your family?

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

Symptoms and treatment of allergy to Penicillin