Introductory Chapter: Deciphering Complexities of Atopic Dermatitis Shifts Paradigms in Treatment

1. Introduction

Atopic dermatitis (AD) in adults can either be a relapsing form of childhood AD or a new adult-onset, the latter being less common. However, the diagnosis of adult-onset AD should be made with caution, as numerous skin conditions may present as eczematous dermatitis in adulthood. Patients who are not eligible or do not respond to intensive topical therapy or phototherapy require systemic therapies [1]. Recent advancements in understanding AD pathogenesis resulted in a real translational revolution and led to the exponential expansion of the therapeutic pipeline. Focusing on biomarkers in emerging treatment studies clarifies the role of each cytokine and immune pathway. Moreover, it allows us to address the unique immune fingerprints of each AD subset. In the future, personalized medicine will be the ultimate goal of this targeted translational research [2]. With the changes in the concepts of both the pathogenesis and treatment approach to AD and the breadth of management options available, choosing the appropriate systemic therapy is becoming challenging.

2. Approach to management of severe atopic dermatitis

There are several factors to consider before starting a systemic treatment in adults with severe AD. To begin with, identifying the causes of recalcitrant disease seems mandatory.

These include lack of adherence to treatment, coexisting allergic contact dermatitis, or photosensitive dermatitis, secondary infection, and vitamin D deficiency.

The lack of practicality of topical treatment leads to decreased adherence over time and persistent disease. Moreover, concerns about adverse effects, like corticosteroid phobia, may lead to inadequate application [1, 3].

Decolonization of staphylococcal aureus infections should be considered in case of recurrent episodes. Chlorhexidine showers, nasal mupirocin, and frequent bathing with or without bleach can help reduce carriage. Family members or cohabitating individuals are often carriers; therefore, treatment of the whole housing unit can stop recurrent infections [4].

Concurrent allergic contact dermatitis has to be considered in all patients with severe AD. Patients have to be patch-tested before being placed on immunosuppressants to avoid false-negative results. Allergens in many topical over-the-counter or prescribed products as well as other common allergens, can all complicate AD [5, 6, 7, 8, 9].

The decision to start systemic therapies is based upon consideration of patient’s adherence to topical therapies, disease severity, frequency of flares, and impact on the patient’s quality of life.

In clinical practice, in addition to visually evaluating the severity and extent of AD, clinicians may assess the impact of the diseases on patients’ quality of life by asking open-ended questions on the intensity of symptoms, frequency of flares, and impact of disease on daily activities, psychosocial life, and sleep. The burden of treatment, including time spent on treatment, cost of medications, and frequency of physician visits, should be assessed as well.

3. Indications of systemic therapy in AD

Several disease severity scales for AD have been validated. However, they are not commonly used in clinical practice and may not accurately identify those in need of systemic therapies. These include: SCORAD (Scoring Atopic Dermatitis), EASI (Eczema Area and Severity Index), POEM (Patient-Oriented Eczema Measure), and DLQI (Dermatology Life Quality Index).

In fact, systemic therapy is required in patients who are not candidates or do not respond to intensive topical therapy or phototherapy.

The main goals of therapy are the improvement of signs and symptoms as well as the overall quality of life.

Over the past decade, our understanding of the pathophysiology and clinical burden of AD has rapidly evolved, with a dramatic increase in new systemic therapies.

While current data is highly promising, supplemental clinical trials are still needed to further elucidate the long-term safety, efficacy, and durability of these treatments. Moreover, comparison studies are also needed to better orient physicians in their choice of systemic therapy [1].

Finally, the combination of clinical efficacy in clinical trials with biomarkers and mechanistic studies has helped select the most promising molecules and will shape the direction of future research. This translational revolution could lead to predicting patients’ responses to targeted therapy, thus guiding the choice of the most suitable treatment.