There are no specific tests for this disease and also the diagnosis of the symptoms can not identify the presence of eczema. Every patient has different symptoms and thus the diagnosis and treatment must be personalized. However, if you go to the doctor, he will inquire about:

Your medical history

Your family history in connection to any diseases or allergies

Your lifestyle and exposure to allergens

The symptoms

The doctor will also carry out medical examination in order to diagnose the presence of eczema. Also, certain tests will be performed by the doctor to identify the skin condition. The following tests may be conducted:

Allergy Skin Test (Skin Scratch/Patch Test) - This is an allergy test to find out if you are allergic to any specific allergen. A small allergen particle is placed under the skin with the needle (scratch test) or on the skin with a tape (patch test). This test will be useful in finding out the presence of allergy; however, this does not accurately detect eczema.

Skin Biopsy- In cases where the doctor thinks that the skin disease is eczema, skin biopsy is helpful in confirming the diagnosis.
Blood Tests- Blood tests do not diagnose eczema but can help to confirm an allergic or atopic tendency by checking the level of IgE.
Eczema can be diagnosed by an allergist, child specialist, immunologist, dermatologist or your doctor.