Do you know the symptoms of skin test allergy?

In our daily lives, doctors usually do skin tests on patients before they need infusions. If symptoms of allergy occur in the skin test, such drugs cannot be injected, so this is a very important step in medical treatment. Usually, blisters during skin tests are a normal phenomenon and do not necessarily mean allergies. People need to have a certain understanding of its allergic symptoms.

1. Why does a blister appear during a skin test?

Many patients often ask, why is there a lump at the injection site? Is this an allergy?

The truth is, the drug for skin test is injected between the epidermis and dermis. There are various tissues distributed between the epidermis and the dermis. These tissues are arranged closely, which will slow down the absorption of drugs and thus cause a skin mump to bulge out.

Some people may ask, why doesn’t this happen during normal drug injections?

This is because our usual injections are intramuscular injections, the muscle tissue is relatively loose, and the drug is absorbed relatively quickly.

So don't worry about the bulge, it's a normal reaction.

What symptoms at the skin test site can indicate an allergy to this drug?

The dermatophytes become larger, redden, and pseudopodia appear, accompanied by an itchy sensation. The whole body may experience dizziness, palpitations, nausea, and even anaphylactic shock.

2. Pseudopodia:

The shape is similar to that of an insect's foot, distributed around the dermis, with red lines that are irregular and of inconsistent length.

The above situations are progressive, which means that anaphylactic shock will occur in the most serious cases. However, usually, if redness occurs, the doctor will highly suspect a positive skin test result and refuse to give the patient this medicine.

On the contrary, if none of the above phenomena occur, then the skin test result can be judged to be negative, which means that the injection can be performed.

3. Three things you must do for skin test

1

Before skin test, do not conceal allergy history

Before the skin test, the patient must truthfully inform the relevant personnel whether he or she has a history of allergy to such drugs, or any family history of allergies.

2

Skin test results were normal, but observation is still required during infusion

Skin tests can only screen for immediate allergic reactions, and may not be able to screen for slow-onset and delayed-onset ones. Therefore, during the medication process, you must observe carefully. If any discomfort occurs, inform the medical staff in time.

3

Stop the drug for three days, and skin test is still required for the next infusion

If the patient stops taking the medicine for three days after infusion and then starts using it again, a skin test must be done again, because the human immune system is constantly changing with the body's response, and regardless of whether you had an allergy before, you may have an allergy later. The same person may react differently to drugs at different times and in different conditions, so unless the injections are repeated, the skin test must be repeated.