The Heterogeneity of Atopic Dermatitis
With common diseases like atopic dermatitis (AD), people often forget how bad the disease can be or how impactful they can be to patients’ physical well-being and their quality of life (QoL). Sometimes practitioners may not realize the degree of morbidity that patients can have with a condition like AD. While not a life-threatening disease, when patients suffer from this chronic skin condition, it impacts every aspect of their life.
Improving patients’ symptoms and QoL is the goal, appreciating that this common disease does not necessarily have a “one-size-fits-all” approach to management. Further understanding the clinical phenotypes, the challenges of diagnosis, the lived experience, and the treatment options for AD will help us better care for our patients.
Clinical Phenotypes of AD
AD can affect all races and ethnicities, but different demographic factors can influence a patient’s individual risk for developing AD or potentially impact their disease course or severity.1 If a patient has a parent or first-degree relative with AD, then the patient will have a higher risk for AD as well.2 AD can be varied in how it presents clinically, especially when considering patient characteristics such as age, race or ethnicity, and other comorbidities.3
The anatomic distribution of AD can vary, and there are some classic presentations in early life compared with later in life.4 When we talk about infantile AD that presents within the first year of life, primarily it presents on the extensor surfaces of the arms and legs, and on the face.5 As infants age into early childhood, the disease migrates to more of the flexural areas. It tends to be more common in the antecubital fossa and the popliteal fossa.6 It can also sometimes involve the hands at that stage. As children get older, AD can often become less severe and sometimes will become more localized to specific areas, such as the hands or feet.
Sometimes we see children who present with very diffuse skin involvement, with more severe disease and more body surface area affected. These patients may maintain that more-severe degree of skin involvement potentially throughout their lives.
We also have patients who do not have a childhood history of AD and develop AD de novo as young adults or even later in life as older adults. We are now seeing more of these nuanced presentations of AD.7 So, it is important to recognize that not everyone is going to fit neatly into a “classic” presentation of AD, either in age at presentation or the anatomic locations where it may develop and where it may evolve.
Being able to recognize AD in all skin types is also critically important for us as dermatologists. We think of AD as being pink or red, erythematous or xerotic plaques, patches, or papules on the skin. For patients with darker skin types, erythema or inflammation can be more challenging to detect and may appear as shades of violet or darker brown, which can lead to misdiagnosis or diagnostic delay. It may also present with more hyperpigmentation, lichenification, or papular disease.
AD Severity
Another aspect of AD heterogeneity involves the inherent disease lability. Seeing a patient on a good disease day may make it harder to know for sure that they have AD or accurately diagnose their disease severity. Following these patients longitudinally will allow us to see them when they are having a more active disease flare. Using patient-reported measures of itch, sleep disturbance, and QoL can also help providers have a better understanding for disease severity. Using applications to track trends and patient outcomes can also help us find solutions quickly.8
For most of our patients, AD is a chronic, waxing and waning disease process. It can go on for several years and sometimes most of the patient’s life, with variations in overall disease severity, locations of disease, and areas most affected.9 The course is characterized by disease exacerbations and other periods where the disease may be quieter. Disease exacerbations can be triggered, and those triggers are different for each patient.
One common trigger is a change in the weather. As it gets colder and less humid in the winter, we often see a period of disease activity or heightened activity for patients with AD. The changes in spring can also cause exacerbations with the increase in pollen in the air. Meanwhile, other patients with AD may get flares in the summer because of increased sweating.
Another common trigger is certain types of clothing. Really tight or restrictive clothing can further irritate the skin. Certain fabrics, such as wool, may be more irritating to patients with AD. Topical products can also be irritating. Heavily fragranced personal care products or products containing certain preservatives or other ingredients, including propylene glycol or other antimicrobial preservatives, are known to be irritating.10
For infants or young children, sometimes food can be a trigger. I might send these patients for allergy testing or for concerns that there may be a specific food that is consistently associated with a disease exacerbation.
Moreover, AD often coexists in what we call the “atopic triad.”1 Patients who have a known history of asthma or allergic rhinitis have a higher risk for AD. AD is often the initial manifestation of atopic triad, but it does not have to be. These are some other patient characteristics that we should consider when evaluating patients for AD and for predicting severity.
Understanding the Patient Lived Experience
While there are many shared signs and symptoms of AD, each patient has a unique experience with their disease—the severity and frequency of each symptom, the diverse myriad of impacts of AD on their lives, and their treatment history.9
Uncontrolled symptoms of AD and the anxiety associated with AD flares can have quite a negative impact on patients’ QoL because of the unpredictable nature of the disease and the intense degree of associated itching, pain, or burning. Sleep disturbances have a pervasive negative impact on patients’ QoL as well. It can be difficult for patients to concentrate in school or at work. The clinical appearance of the skin can also really impact patients from a psychosocial perspective. If they have excoriation or areas of the skin that are bleeding or filtering, it can be embarrassing for patients. They may want to hide their skin, be less active, or engage less in their usual day-to-day activities. In addition, the time spent managing the disease can be significant, and many patients use and have used multiple treatment approaches.
Addressing and incorporating the patient perspective in care validates their experience and can help identify the best approaches to alleviate symptoms and QoL burdens. As a dermatologist, it is so rewarding when you can work with your patients to help them feel better. They are often so grateful for the global improvement in how they feel and how they live their life on a day-to-day basis. A lot of my patients talk about the mental fatigue of having to deal with AD. When I can get them to a better place and the disease is relatively quiet, my patients often say they have such a weight lifted off their shoulders.
Conclusion
Remember that not every patient is going to fit neatly into “infantile-onset AD” that follows the classic anatomic distribution and improvement with aging. Patients can present in many ways and at any age, and have varied lived experiences with the disease. Staying informed of current literature on AD and taking steps to understand the physical, mental, and QoL patient impacts can be helpful in designing and refining treatment plans for this chronic and heterogenous disease.
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4. Silverberg JI, Vakharia PP, Chopra R, et al. Phenotypical differences of childhood- and adult-onset atopic dermatitis. J Allergy Clin Immunol Pract. 2018;6(4):1306- 1312. doi:10.1016/j.jaip.2017.10.005
5. Halkjaer LB, Loland L, Buchvald FF, et al. Development of atopic dermatitis during the first 3 years of life: the Copenhagen prospective study on asthma in childhood cohort study in high-risk children. Arch Dermatol. 2006;142(5):561-566. doi:10.1001/archderm.142.5.561
6. Siegfried EC, Hebert AA. Diagnosis of atopic dermatitis: mimics, overlaps, and complications. J Clin Med. 2015;4(5):884-917. doi:10.3390/jcm4050884
7. Silverberg JI. Adult-onset atopic dermatitis. J Allergy Clin Immunol Pract. 2019;7(1):28-33. doi:10.1016/j.jaip.2018.09.029
8. Turn your whys into wise. EczemaWise. National Eczema Association. Accessed March 4, 2022. https://www.eczemawise.org/
9. Silverberg JI, Lei D, Yousaf M, et al. Association of itch triggers with atopic dermatitis severity and course in adults. Ann Allergy Asthma Immunol. 2020;125(5):552-559. e2. doi:10.1016/j.anai.2020.06.014
10. McGowan MA, Scheman A, Jacob SE. Propylene glycol in contact dermatitis: a systematic review. Dermatitis. 2018;29(1):6-12. doi:10.1097/DER.0000000000000307
