Exploratory study of clinical, histological, and skin microbiome characteristics of head and neck dermatitis in adult atopic dermatitis

Abstract

Head and neck dermatitis (HND) is a unique subtype of atopic dermatitis (AD) which commonly manifests in late adolescence or adulthood. HND’s presentation of chronic eczematous lesions with diffuse erythema and itching or pruritus is often refractory to therapy and affects patient’s quality of life. However, HND is often underappreciated in clinics and detailed studies characterizing this specific AD subtype is very limited.

This study sought to analyze the clinical and histological characteristics of HND patients. Further, as there are a growing number of AD studies focusing on the role of skin microbiome in the disease pathogenesis, microbiome analysis of HND patients in comparison to non-HND (N-HND) AD and normal (NL) subjects was performed.

The results showed HND patients comprising approximately 2.4% of AD patients in an outpatient clinic setting. Compared to N-HND patients, HND initially presented with more severe disease status and elevated serum total IgE and serum specific IgE reactivity to Dermatophagoides farinae. Histologically, HND specimen showed thickened epidermis with increased vascular components and dermal inflammatory infiltrates. Although staining intensity did not differ between HND and NL specimen, the absolute number of staining intensity measurement was all higher in HND, supporting a contributory role of pro-inflammatory cytokines, chemokines, and neuroinflammatory factors in the HND pathogenesis. Lastly, the microbiome analysis of HND in comparison to N-HND AD and NL subjects showed no significant difference in the diversity of bacterial community.

Combining findings from this study reaffirm that HND is a clinical subtype of AD that needs distinction from classical AD. In the future, further investigation of skin microbiome and inflammatory factors involved in vasculatures of AD facial regions will lead to development of potential therapeutic targets.