The scratch test is similar to the prick test, except the skin is abraded with a lancet over the area where the allergen solution was applied.

The allergen then gets under the skin and – if an allergy exists – causes swelling.

The scratch test is non-specific and rarely used.

In an intracutaneous test, a solution containing the allergen is injected under the skin.

If the patient is allergic to the substance, an allergic reaction appears on the skin within minutes (swelling, redness, itching.)

The test is very sensitive, but general allergic symptoms can appear – the intracutaneous test is therefore used mostly as an addition to the prick test in certain cases.

For the rub test, the source of the allergens, instead of just solutions containing the allergens, are rubbed directly onto the skin. This means the substances themselves – food or other substances- are rubbed onto the skin of the lower arm.

In order to be sure that any reaction is not a result of the rubbing, the other arm is rubbed with the same intensity with a saline solution; the reactions on both arms are then compared.

The epicutaneous test is especially useful for identifying the cause of a contact allergy. Patches containing suspected allergens are applied to the skin. The patches are removed after two days, and the doctor examines the skin’s reaction. After another 24 hours the skin is examined again for any new developments.