Allergy to medications is an abnormal reaction of the immune system to that medication . It is important to know that no medication is free of allergy.
This means that all medicines, whether over-the-counter, prescribed by the doctor or those made up of herbs, can cause allergies. However, some produce it with higher incidence than others .
So that the symptoms that occur can be considered as allergy to drugs, they have to appear through immunological mechanisms. If they are produced by other mechanisms, it should not be called allergy, although the final symptoms are the same. Both allergies and other types are part of what are called adverse drug reactions .
Symptoms of allergy to medications
Once the drug that will develop the allergy in the patient is taken, the characteristic symptoms of the reaction usually appear at the time . However, there are other symptoms, especially cutaneous ones, that may appear later, even weeks.
Some characteristic symptoms of allergy to medications are:
- Skin rash: also considered redness, skin inflammation, skin lesion, blushing, salpullo or erythrema. These conditions involve changes in the color or texture of the skin.
- Urticaria : is a disease of the skin characterized by edematous skin lesions. It is usually accompanied by itching or burning.
- Swelling and itching
- Shortness of breath and whistling when breathing.
- Tearful and itchy eyes.
It is possible that in some cases an anaphylactic reaction can be triggered by drug allergy. If this occurs, the patient’s life may be in danger, as it causes widespread dysfunction of the body’s systems.
When an anaphylactic reaction is triggered, the airways narrow, which causes difficulty in breathing . Nausea and cramps also appear, as well as vomiting and diarrhea. On the other hand, patients who are under these conditions may suffer seizures, loss of consciousness, weak and accelerated pulse and falls in blood pressure.
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Other signs and symptoms
As mentioned above, there are some allergy symptoms that are triggered in a longer period of time after the administration of the medication. In addition, some of them may persist in time as well. Examples of these reactions can be:
- Serum disease: this disease can occur with fever, joint pain, rashes, swelling and nausea.
- Anemia : characterized by having values of red blood cells below normal. This situation results in fatigue, irregular heartbeat, shortness of breath, etc.
- Eosinophilia and systemic symptoms : what causes rash, elevation of white blood cells, generalized swelling, inflammation of the lymph nodes and recurrence of infection by latent hepatitis.
- Nephritis : inflammation of the kidneys can cause fever, blood in the urine, confusion and other symptoms.
How is medication allergy diagnosed?
To prevent anaphylactic reactions or other unpleasant situations for patients, it is essential to have an accurate diagnosis . Some research has shown that the drug allergy can be diagnosed in excess and that patients who claim to have it have never confirmed it.
If an adequate diagnosis is not made, it may happen that patients use less appropriate antibiotics and more expensive medications. Therefore, the doctor must perform a physical examination and some questions.
The patient must collaborate with the doctor when giving details about the appearance of symptoms, the duration of treatment and about the improvement or worsening of symptoms. The tests that medical personnel must perform are:
- Skin tests : A small amount of the suspected drug is given to the skin with a needle that scrapes the skin, with an injection, or with a patch. If the medication produces an allergy, an itchy red bump will appear.
- Blood tests or blood tests : this technique is done to rule out other diseases that could cause the symptoms. However, they are not used frequently due to limited research on their accuracy.