Typical skin changes may include:

• Blisters with oozing and crusting
• Ear discharge or bleeding
• Raw areas of the skin from scratching
• Skin coloring changes -- more or less coloring than the normal skin tone (See: Skin abnormally dark or light)
• Skin redness or inflammation around the blisters
• Thickened or leather-like areas, called lichenification, which can occur after long-term irritation and scratching

Both the type of rash and where the rash appears can depend on the age of the patient:

• In children younger than age 2, skin lesions begin on the face, scalp, hands, and feet. It is often a crusting, bubbling, or oozing rash.
• In older children and adults, the rash is more commonly seen on the inside of the knees and elbows, as well as the neck, hands, and feet.
• During a severe outbreak, rashes may occur anywhere on the body.

Itching, which is sometimes intense, almost always occurs. Itching may start even before the rash appears.

Diagnosis is primarily based on:

• Appearance of the skin
• Personal and family history

The health care provider should examine the lesions to rule out other possible causes. A skin lesion biopsy may be performed, but is not always needed to make the diagnosis.

Allergy skin testing may be helpful for people with:

• Difficult-to-treat eczema
• Other allergy symptoms