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If the allergist, after receiving the information from the referring physician and from the patient (and after carrying out prick tests in the case of food allergens), thinks that there is a need of a drug or food challenge to confirm or rule out an allergy, then he will refer the patient to the allergy clinic in the hospital where a challenge can be performed.
After a consultation with an allergist in the hospital, the testing will start. In the case of a food allergen the hospital doctor may decide to redo the prick tests. Then, the patient will receive a small amount of the food or drug suspect of eliciting an allergy, through the mouth and under controlled conditions, so that if there is a reaction he will immediately receive the necessary medical treatment. In the absence of a reaction, the dose of the food or drug suspect of eliciting an allergy will be escalated until a therapeutic dose of the drug or a normal food portion is reached. The patient will be monitored for two hours after the last dose. If still there is no reaction, the patient is released with a summary that explains that there was no reaction during the surveillance period. However, to be sure that there is no allergy, we will have to wait for another week because there are delayed reactions that may occur even several days after the challenge. However, dangerous reactions occur during the observation period, so that no dangerous response is expected at home, if at all.
If after a week there is still no reaction, we can rule out allergy to the tested drug or food.
If at any stage there is a reaction, so the patient will be diagnosed as allergic to the tested drug or food.
The reason to make these challenges only in a hospital setting is that there is a possibility of a dangerous reaction and therefore the patient must be tested where all the appropriate infrastructure to handle a reaction is available. In addition, the whole test sometimes takes some hours. Therefore, the appropriate framework to test is in the hospital day care.
If the allergist, after receiving the information from the referring physician and from the patient, thinks that there is a need to test allergy to penicillins, then he will refer the patient to the allergy clinic in the hospital where a penicillin test can be performed.
Once in the hospital, the test begins by skin prick testing different components of penicillins. If there is no response, diluted penicillins are injected under the skin in several rounds, each round using a more concentrated material until a skin reaction occurs, if at all.
Between each round there is an observation period of around 15 minutes. If there is no response to the skin injections even in the most concentrated round, the next step is a penicillin challenge, in which the patient will receive a small amount of oral penicillins, under controlled conditions, so that if there is a reaction he will immediately receive the necessary medical treatment. In the absence of a reaction, the dose of penicillins will be escalated until a therapeutic dose is reached. The patient will be monitored for two hours after the last dose. If still there is no reaction, the patient is released with a summary that explains that there was no reaction to penicillins during the surveillance period. However, to be sure that there is no allergy to penicillins, we will have to wait for another week because there are delayed reactions that may occur even several days after the challenge. However, dangerous reactions occur during the observation period, so that no dangerous response is expected at home, if at all.
If after a week there is still no reaction, we can rule out penicillin allergy.
If at any stage there is a reaction, so the patient will be diagnosed as allergic to penicillins.
The reason to test penicillins only in a hospital setting is that there is a possibility of a dangerous reaction and therefore the patient must be tested where all the appropriate infrastructure to handle a reaction is available. In addition, the whole test sometimes takes some hours between the skin tests and the penicillin challenge. Therefore, the appropriate framework to test is in the hospital day care.
Spirometry tests lung function and helps in the diagnosis and monitoring of asthma.
Spirometry is a simple and non-invasive test in which the patient is asked to blow into a device (through a disposable mouthpiece) with all his force several times.
The device measures the speed with which air is exhaled from the lungs of the patient. When there is resistance to the exhalation we speak about an obstructive pattern, which is typical of asthma.
Even after the diagnosis of asthma, monitoring over time with spirometry helps to understand the state of the disease and to optimize asthma treatment.
The allergist may order some blood tests:
The vast majority of patients do not need blood tests.
RAST (Radio Allergo Sorbent Test) is a test that checks the existence of specific antibodies against various elements suspected of being the cause of allergy (inhaled or food). Today the test is usually performed using another technology: ELISA (Enzyme-Linked Immuno Sorbent Assay).However, it continues to be called RAST by some persons.
For this test, a blood sample is taken. A few days later the results reflect the existence or not of antibodies against the inhaled particles or foods tested. This test is less useful than the prick test but there are times that due to a skin disease, inability to stop anti-histamine drugs, the physician is forced to order this test instead of performing a prick test.