Thiomersal is used in patch testing for people who have dermatitis, conjunctivitis, and other potentially allergic reactions.

History is equally important after patch testing.

Studies concluded from patch testing show synthetic fragrances are made of many ingredients which cause allergic reactions.

Skin allergy testing (such as patch testing) is available for certain foods and venoms.

If the suspicion is high in spite of negative patch testing, further investigation might be required.

Dermatologists may refer patients with suspected food allergies for patch testing.

Often, patch testing for food allergies is not necessary, but in selected individuals it may be helpful.

Other types of skin tests include patch testing and intradermal testing.

It is the cause of contact allergic reactions in 2-3% of eczema patients undergoing patch testing.

A complete patient history combined with negative allergic patch testing is usually necessary to reach a correct diagnosis.