The following has been adapted from transcripts of Expert Insights in Atopic Dermatitis: Confronting Issues and Challenges Beneath the Surface, a multimedia content series examining atopic dermatitis at levels deeper than the skin’s surface. This series is developed in partnership with the National Eczema Association and is made possible through funding from AbbVie.
Diagnostic Challenges, featuring Vivian Shi, MD, FAAD
Important Considerations for an Accurate AD Diagnosis
How do we get to an appropriate and timely diagnosis for atopic dermatitis (AD)? That is the million-dollar question. If we cannot make a timely diagnosis, we cannot design an appropriate and individualized treatment, and patients won’t get better. To make the correct diagnosis, one of the most important things is to actually recognize the different patterns of AD: how the skin feels (symptoms) and looks (signs) (Table 1).
Recognizing symptom is the first step in diagnosing AD. Unlike many other conditions where rash develops before itching, eczema is the itch that rashes, meaning itching may start before any visible rash. As a natural reflex, we scratch where the skin itches, then rash development which leads to even more itching – this is known as the “itch-and-scratch cycle”. An important goal of AD treatment is to help patients break this cycle.
A commonly used diagnostic criteria for AD are the Hanifin-Rajka criteria, which is useful for identifying the classic signs of AD. There are a number of major criteria and minor criteria (Table 2), but at the base of the diagnosis, the patient should have rash and itching. While AD can develop all over the body, there are classic areas where it develops in a diagnostic pattern depending on the age of the patient. For example, when babies develop AD lesions, these typically present on the cheeks. As the child ages, they develop lesions more in the skin folds, or the inner side of the elbows and the back of the knees.
When we get to adulthood, there is a progression with more arm, leg, hand, and foot involvement.
Diagnosing classic AD, many times, is checking off a number of those criteria boxes, but the real challenge is that not every case of AD will present exactly like the textbook definition. There is a wide spectrum of eczematous presentations. The word eczema just means dermatitis or inflammation of the skin of any kind; any time the skin has redness, swelling, or even itching, the symptoms can be called dermatitis or eczema. These symptoms may signal a number of other conditions, including seborrheic dermatitis or irritant hand dermatitis. Homing in on the actual diagnosis will allow us to design the appropriate treatment and give our patients and caregivers appropriate information on what to expect in the long term.
AD is remitting and relapsing disease; there are good days and bad days. The treatment goal is to have more good days and less bad days. When the patient comes to see me with their family, we are only catching them in a snapshot which may not tell the full story of their AD in between doctor visits. I tend to ask my patients to show me some photographs of their affected areas. Now that we are in the era of smartphones, my job has gotten a lot easier, as patients can take photos to track their disease progression. Even when the skin doesn’t look that severe during the doctor visit, their documentations and photo records allow me to able get a fuller picture of how their skin looked in between visits. Conversely, if the skin is really bad on the day that they are visiting, I can get a better idea about what is the best they have looked in this anatomical area.
There are also other tricks for diagnosing AD. Many patients often have a cluster of allergy diseases, including AD, food allergies, asthma, and hay fever (also known as allergic rhinitis or seasonal allergies) . Many times, even when the skin does not have an active eczema rash, I can use other clues to determine whether that the patient is has an “allergic” tendency. One of these common signs are Dennie-Morgan lines, or prominent skin folds on the lower eyelid. In addition, many of these patients will have a darker skin color around the eyes and the nose from chronic rubbing of these areas due to itching and runny nose. Patients with eczema may also have hyperlinear palms, in which the lines on their palms are more prominent, rough, and groovy. These tricks can help identify a patient who is at risk for AD.
Experiences of Racial-Ethnic Minority Groups
In general, not enough is understood regarding conditions in skin of color skin; this is true in AD as well. The majority of the research on skin and on AD mainly has been done in developed countries and in Caucasian individuals. Most of the dermatology textbook uses Caucasian photos and cases. But this is changing with the rapidly growing social awareness. It is important that we bring attention to this matter and knowledge gap (Table 3).
The clinical presentation of AD can be different in various skin types. AD in an Asian person can looks more similar to that of psoriasis in a Caucasian person than of AD. In my experience of volunteering in Southeast and East Asia earlier in my career, I admittedly had trouble distinguishing psoriasis and AD in these patients. This distinction is getting more attention through the research of physician scientists such as Dr Emma Guttman, showing exactly the above.