Hymenoptera are divided into families, the main ones being bees and wasps. The former include the common bee and the "scurge", the latter include the common wasps (there are many different species) and the polistas (a small wasp that is usually found on roofs and in attics and builds a paper-like nest). Their poisons have some common allergens but also some others that are specific to each family - that is, if they are present in the bee they are not present in the wasp and vice versa. Because of this, a patient may be allergic to only the bee, only the wasp or both. This is why it is of particular importance to accurately identify the cause of the allergy.

Something particularly important must be emphasized here that often causes confusion and misunderstandings. Tests done to investigate allergy show whether a patient is sensitized. This does not necessarily mean that they are allergic! That is, it may be that all tests and examinations "show allergy" but the bites are tolerated without any problem. This has the following important consequence: tests are necessary and extremely useful in case of a positive history of reaction, i.e. in case someone has already been bitten and a certain degree of reaction has been caused. Conversely, if there is no history of a sting or if it has only caused a mild, local reaction, the tests can be done but their results are of dubious value. In other words, unfortunately at this stage, population screening has a low degree of reliability.

The tests leading to a correct diagnosis are divided into two categories. The first is a blood test carried out in special laboratories. These are called RAST or CAP, which show whether there are specific antibodies in the patient's blood and which poison they recognize. In recent years research has progressed a lot and blood tests can very accurately distinguish the 'guilty' insect. The second category of tests are skin prick tests and intradermal tests. These confirm the findings of the blood test and also give a measure of the severity of the reaction. The simultaneous performance of both tests is essential as it gives the maximum possible information.

Dimitris Mitsias
ALLERGIST
Allergy Unit NKUA