What Is the Diagnostic Criteria for Atopic Dermatitis?

Atopic dermatitis (AD) is a relapsing skin condition that doesn’t look exactly the same on everyone. Some people just have redness, dry skin, and itchiness, while others have papules, blisters, or weepy skin. Over time, some people with AD develop thickened skin, called lichenified skin.

The American Academy of Dermatology (AAD) has developed diagnostic guidelines to help doctors properly diagnose AD. These clinical recommendations were determined by an extensive review of the published data, as well as consideration of other, previously published diagnostic criteria.¹

Itching is an essential feature of atopic dermatitis

The AAD diagnostic guidelines have identified the following essential features which must be present to classify a skin condition as AD:

• • Pruritus, or itching
  • Eczema or inflamed skin that has typical age-specific patterns and a chronic or relapsing history¹

The age-specific patterns of AD have been identified as:

• In infants and young children: eczema on facial, neck, and extensor (outer surfaces of the limbs) surfaces
• In any age, current or previous eczema on flexural (inner surfaces of the joints, like the inner crease of the elbow or knee) surfaces¹

Other important features

In addition to the essential features identified by the AAD guidelines, the following important features are seen in most cases and add support to the diagnosis of AD:

• Early age of onset
• Atopy, or a genetic predisposition to develop an allergy, which may be personal or family history; some people with AD also have immunoglobulin E (IgE) reactivity*
• Xerosis, or dry skin¹

*IgE reactivity – Immunoglobulin is a type of protein that is part of the immune system and that acts as an antibody to attach and destroy foreign substances. There are five different types of immunoglobulin, and the IgE protein is found in increased levels in people with allergy. IgE causes the body to release histamine when it comes into contact with an allergen.^2,3

Symptoms associated with atopic dermatitis

The AAD diagnostic guidelines for AD have identified associated features that may help suggest AD but are too nonspecific to be used for defining the condition because they are also symptoms of other skin conditions.

The associated features include:

• Atypical vascular responses, or
• Keratosis pilaris – when the skin has tiny, hard bumps around hair follicles
• Pityriasis alba – dry, white patches
• Hyperlinear palms – extra creases in the palms of the hands
• Ichthyosis – dry, scaly, or thickened skin
• Involvement of the skin around the eyes
• Involvement of the skin around the mouth or ears
• Involvement of the hair follicles in the skin
• Lichenification, or thickened patches of skin
• Prurigo lesions – itchy nodules with skin eruptions¹

Excluding other conditions

The AAD guidelines recommend that a diagnosis of AD also depends on excluding other conditions, such as:

• Scabies
• Seborrheic dermatitis
• Contact dermatitis (irritant or allergic)
• Ichthyoses
• Cutaneous T-cell lymphoma
• Psoriasis
• Photosensitivity dermatoses
• Immune deficiency diseases
• Erythroderma of other causes¹

Disease severity and quality of life assessment

There is no single, “gold standard” measurement for disease severity or quality of life assessment for AD. Several different tools exist and are used in clinical trials and research. The different features of the disease, as well as the extent or amount of skin affected, generally measure disease severity.

Quality of life can be assessed by a physician questioning the patient (or the parents of a young child) about itch, sleep, impact of the condition on daily activities, and the persistence of the disease. The intensity of itch experienced is a highly subjective measure. Parents of young children or older individuals with AD can measure this for themselves using a simple rating, such as 1 to 5 with 1 being no or mild itch and 5 being severe itch.¹