Atopic dermatitis cannot be diagnosed with a test, like diabetes for example. Atopic dermatitis can only be diagnosed clinically. That means that in order for you to be diagnosed with Atopic dermatitis your doctor or dermatologist must see certain signs on your skin.
Sometimes even these clinical signs are not enough to diagnose Atopic Dermatitis and in such cases additional clinical features are required. The most important additional features are a personal or family history of atopy (Atopic Dermatitis, Asthma or Hay fever), itching and a history of the skin disease coming and going over a period of months to years.
In summary, the major diagnostic features of Atopic Dermatitis are:
- The typical skin signs
- a Personal or family history Atopic Dermatitis, Asthma or Hay fever
- Chronicity of the condition
The typical skin signs of Atopic dermatitis varies with age. In infants the face, scalp, front part of the legs and back part of the arms are most often affected. In adults the disease seems to switch to the opposite side of the limbs where it is the back part of the legs (especially the skin folds behind the knee), the front part of the arms (especially the skin folds at the elbow) and other flexural areas that are characteristically affected. These are not hard-and-fast rules and any area of the skin can be affected.
In addition to the above mentioned major features of Atopic Dermatitis the following minor features can also help in making the diagnosis of Atopic Dermatitis.
- Xerosis (Skin dryness)
- Denny-Morgan skin folds. These are prominent skin folds in the lower eyelid.
- Centro-facial pallor. The skin of the central part of the face appears lighter than the periphery.
- Peri-orbital darkening. Darkening of the skin around the eyes.
- Pityriasis alba (a slight powdery-white scaling on the cheeks)
- Keratosis Pilaris, which can be felt as a roughness on the upper-outer arms especially.
- a Raised IgE – antibody level on a blood test
- an Increased number of eosinophils (a type of white blood cell) in the blood
- Seasonality of the condition
- a Positive skin prick test to various substances
- Itching when sweating
- Prominent skin folds along the front of the neck
- Prominent dryness on the shins that can have a puzzle-like appearance due to large dry flakes
- Hand en foot dermatitis
- Nipple dermatitis
- Red inflamed eyes
- A sensitivity to wool
Please note that blood tests and skin prick tests cannot be used to diagnose Atopic Dermatitis! They make up just 3 of the minor features of Atopic Dermatitis and are therefore relatively unimportant when it comes to diagnosing Atopic Dermatitis.
It is important to realize that not any single factor alone are diagnostic of Atopic dermatitis. The diagnoses can be made with confidence only if at least 3 of the 4 major features are present together with 3 of the minor features of Atopic Dermatitis.