An allergy is an immune reaction of the body to certain substances which normally don’t react. This is notable on the skin in the shape of bubbles, pimples scales, redness or itching.

There are different sorts of allergies but almost every allergic reaction of the skin is from the slow type: the contact allergy. They are called ‘slow’ because the symptoms of the allergy are only visible after 1 or 2 days.

After the first contact with the allergen, the sensibilisation finds place or you become oversensitive to it. This can last 5 to 7 days. No external signs are visible however it means the starting shot for the immune systeme to take action. The white bloodcells begin recognizing the allergen. After a second contact, the tiny cells in the skin react by producing active chemicals. These active chemicals in the skin produce irritation resulting in itching rashes.

Why an allergy for a certain substance appears isn’t clear yet. However three general factors are of major importance concerning the contact allergy:

• The allergen has to react with proteins from the skin
• Genetics play an important role: an estimated 10 to 20% of the population has a tendancy towards allergies
• Infavorable circumstances with the first contact raise the risk for an allergy: for example a decreased barrier function of the skin (a healthy skin is therefore very important)

When a patient or a doctor suspects an allergy, a case history will be taken which will include information on home and work, living habits and time of year when the symptoms occur. The doctor will decide from this what tests are necessary. He will then carry out skin tests (patch test and / or prick test) to different materials, and the results of these tests, together with the case history, will help him decide what treatment is needed.

An allergy for a certain substance is mostly for life. It can only be prevented by avoiding the known allergen.

When a product is labeled "hypoallergenic" it means it will less likely cause an allergic reaction. So, hypoallergenic does not mean non-allergenic. It is not an absolute guarantee that a skin cannot be allergic to a product, but it gives you extra assurance that the skin has less of a chance of becoming oversensitive to it.