Clinical Relevance of Skin Pain in Atopic Dermatitis

October 2020 | Volume 19 | Issue 10 | Original Article | 921 | Copyright © October 2020


Published online September 16, 2020

Sonja Ständer MDa, Eric L. Simpson MDb, Emma Guttman-Yassky MDc, Jacob P. Thyssen MDd, Kenji Kabashima MDe, Susan G. Ball PhDf, Maria Jose Rueda MDf, Amy M. DeLozier MPHf, Jonathan I. Silverberg MDg

aDepartment of Dermatology and Center for Chronic Pruritus, University Hospital Münster, Münster, Germany bDepartment of Dermatology, Oregon Health & Science University, Portland, OR; Oregon Clinical & Translational Research Institute, Oregon Health & Science University, Portland, OR cDepartment of Dermatology and the Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY dDepartment of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark eDepartment of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan; Singapore Immunology Network (SIgN), and Skin Research Institute of Singapore (SRIS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore fEli Lilly and Company, Indianapolis, IN gDepartment of Dermatology, The George Washington University School of Medicine, Washington, DC

Abstract
Skin pain is increasingly recognized as an impactful symptom in atopic dermatitis (AD) because of its association with patient discomfort, disease burden, and reduced quality of life. Although the nature of skin pain in AD has not been systematically studied and is therefore not well understood, patients report soreness, discomfort, and tenderness that may reflect peripheral and central pain sensitization. The high prevalence of skin pain suggests that it is not adequately addressed by current therapies for AD and may be undertreated compared with other symptoms. This review discusses the clinical relevance of skin pain with respect to its experience, pathophysiology, relationship with itch, and treatment implications. Recent studies suggest that skin pain presents as a neuropathic symptom independent from itch and the “itch-scratch cycle”, and poses a unique burden to patients. Recognition of the significant consequences of skin pain and discomfort should reinforce the need to assess and treat this symptom in patients with moderate-to-severe AD.

J Drugs Dermatol. 2020;19(10)921-926. doi:10.36849/JDD.2020.5498

INTRODUCTION

Atopic dermatitis (AD) is a skin disorder characterized by chronic relapsing pruritic eczema resulting from altered skin barrier function and neuroimmune dysregulation.1 Moderate-to-severe AD can result in functional impairment, sleep disturbance, and anxiety and depressive symptoms.2,3 While nearly all people with AD suffer from the hallmark symptom of itch,3-5 skin pain is another sensory symptom of the condition, but one that is less recognized by dermatologists and treatment guidelines. Skin pain in AD has been underappreciated for multiple reasons including: a lack of awareness by patients and clinicians; a lack of a common lexicon for describing skin pain; a view that skin pain is a corollary of physical signs of AD that will improve after treating skin lesions; and the assumption that skin pain and itch cannot be experienced simultaneously.

Until recently, little was known about the frequency of skin pain, its causes, and its impact on the quality of life (QoL) for patients with AD. In this article, we establish the clinical relevance of skin pain in AD by reviewing new evidence of its nature, pathophysiology, prevalence, and consequences. We also detail why this symptom should be considered in AD assessment and treatment.

What is meant by skin pain in AD?
The concept of pain, including skin pain, is complex and multifactorial. How pain is experienced differs among individuals, and what a dermatologist conceptualizes as skin pain may vary widely from the patient’s experience of this symptom.

Qualitative studies provide greater patient insight into skin pain. In a natural language processing and centrality analysis, word choice and experiences of patients with AD were examined from an international cross-sectional, open-ended survey.6 Itch was the most impactful symptom, but pain also led to a significant, distinct burden for patients. Pain was linked to itch in some patients, and to embarrassment and annoyance in others, suggesting both physical and emotional consequences.

Patients with AD use different words to describe their experience of skin pain. Many use neuropathic descriptors, such as “burning”, “stinging”, “tingling”, and “pinprick-like”.7-10 In one study, 36 of 43 (84%) patients with AD reported skin pain, with 67% of them describing it as a “burning sensation” or “soreness or discomfort”. Others characterized it as a “stinging sensation” (47%), “sensitivity” (44%), or “stabbing feeling”