Seborrheic Dermatitis Revisited: Pathophysiology, Diagnosis, and Emerging Therapies—A Narrative Review

Background: Seborrheic dermatitis (SD) is a chronic, recurrent inflammatory dermatosis that primarily affects seborrheic areas such as the scalp, face, and upper trunk. Its etiology is multifactorial, involving sebaceous gland activity, immune dysregulation, skin barrier dysfunction, and alterations in the microbiome, particularly an overgrowth of Malassezia spp. Objective: This review provides an updated overview of the pathophysiological mechanisms of seborrheic dermatitis and critically examines current therapies and emerging treatments. Methods: A narrative review of the recent literature was conducted, including preclinical studies, clinical trials, and real-world evidence regarding SD pathogenesis and therapy. Special attention was paid to molecular pathways, microbiome-modulating strategies, and novel therapeutic agents. Results: Advances in transcriptomic and microbiome profiling have revealed a complex immunoinflammatory environment in SD, involving predominantly Th1, Th17, and Th22 axes. Conventional therapies are mainly based on antifungals, topical corticosteroids, and calcineurin inhibitors. However, new therapeutic approaches are under investigation, including PDE4 inhibitors (roflumilast, crisaborole, and apremilast), topical and oral JAK inhibitors, probiotics, and microbiome-targeted therapies. These agents offer promising results in selected patients, particularly those with refractory disease or facial involvement. Conclusions: SD remains a challenging condition due to its relapsing course and limited long-term therapeutic options. Emerging therapies represent a valuable opportunity to address unmet clinical needs, particularly in patients with severe, recurrent, or treatment-resistant forms.