Penicillin Allergy

1 What is Penicillin Allergy?

Penicillin allergy refers to the allergic reaction caused by an exaggerated immune response to the drug penicillin.

About 10% of the people are affected by this drug allergy. As in other forms of allergy, symptoms of penicillin allergy may range from mild to severe.

Mild symptoms include skin rashes and itching, while severe anaphylactic reaction may be seen in others.

Anaphylactic response to the drug may result in life-threatening situation.

Anyone who is allergic to penicillin may be allergic to other antibiotics belonging to the same class. Hence the entire group of antibiotics should be avoided. 

2 Symptoms

These symptoms of penicillin allergy may appear within few hours of taking the drug:

  • In some cases reaction may appear after few days or week, or result in serious, life-threatening symptoms called anaphylaxis. This is characterized by constriction of airways, difficulty in breathing, sudden lowering of blood pressure, and loss of consciousness.
  • Some people may have rapid or weak pulse rate, bluish skin, nausea, vomiting, or slurred speech as symptoms of drug allergy.

Penicillin may cause some other rare conditions like

  • Serum sickness – this condition is characterized by joint pain, nausea, vomiting, fever, and rashes on skin.
  • Anemia – anemia induced by drug results in reduced levels of red blood cells, weakness, fatigue, and shortness of breath
  • Drug reaction – eosinophilia, swelling in lymph nodes, and rashes are the symptoms of drug reaction.
  • Nephritis – inflammation of kidneys result in fever, blood in urine, and confusion as symptoms.

3 Causes

Penicillin allergy is caused when the immune system over reacts to the antibiotic drug.

On first exposure, the immune system triggers the production of antibodies against this drug. On further exposure, these antibodies activate chemicals that cause the typical signs and symptoms of drug allergy. This happens in people who are sensitive to the drug.

Penicillin belongs to the class of drugs called beta lactams. Cephalosporins are other group of beta lactams associated with allergic reactions.

People with penicillin allergy may be associated with allergy to other penicillin or cephalosporins.

4 Making a Diagnosis

A thorough exam and appropriate diagnostic tests are essential for an accurate diagnosis of penicillin allergy.

Physical examination and the timing of symptoms provide valuable information regarding penicillin allergy.

Skin test and challenge test are also used to confirm the diagnosis. In a skin test, a small amount of the drug is administered to the skin with the help of a probe, or through an injection. Presence of itchy, bumps on the skin at the test site indicates drug allergy.

In graded challenge test few doses of the suspected drug is given by gradually increasing the dose. If no reactions are seen even after reaching the therapeutic dose, the person may not have an allergy to the drug.

The test is conducted for other drugs with similar chemical properties to rule out chances of other drug allergies.

5 Treatment

The first step in the treatment of penicillin allergy is the withdrawal of the drug, once it is suspected.

Medications and desensitization are the two major methods used in the treatment of drug allergy.

Medications are used to reduce the effect of different symptoms of allergy.

Antihistamines block the action of histamines, chemicals that cause allergy symptoms.

Inflammation is controlled by using corticosteroids. Anaphylaxis is treated with epinephrine injections.

In desensitization method, small doses of the antibody is given to the patient.

The dose is gradually increased over the whole day.

6 Prevention

Avoiding penoicillin is the best way to prevent penicillin allergy.

Remember to mention about the allergy to healthcare workers.

Wear a bracelet that contains information about the condition, causes and symptoms.

Always carry epinephrine shot if there is a history of serious reactions.

7 Alternative and Homeopathic Remedies

Cold compress is the alternative remedy used to reduce the symptoms of penicillin allergy.

8 Lifestyle and Coping

Lifestyle modifications are necessary in order to cope with penicillin allergy.

Remember to inform healthcare workers regarding the allergy.

A bracelet that provides the details of drug allergy is ideal for emergency situations.

Those who have serious symptoms should carry the epinephrine shot for immediate control.

9 Risks and Complications

Anaphylaxis is the main complication of penicillin allergy.