Pathophysiology, Disease Presentation, and Treatment Strategies for Seborrheic Dermatitis
abstract
This abstract is available on the publisher's site.
Access this abstract now Full Text Available for ClinicalKey SubscribersSeborrheic dermatitis (SD) is a common skin disease with signs and symptoms that may vary by skin color, associated medical conditions, environmental factors, and vehicle preference. Diagnosis of SD is based on presence of flaky, "greasy" patches, and/or thin plaques accompanied by erythema of the scalp, face, ears, chest, and groin and is associated with pruritus in many patients. The presentation may vary in different skin types and hyper- or hypopigmentation may occur, with or without erythema and minimal or no scaling. While the pathogenesis is not certain, 3 key factors generally agreed upon include lipid secretion by sebaceous glands, Malassezia spp. colonization, and some form of immunologic dysregulation that predisposes the patient to SD. Treatment involves reducing proliferation of, and inflammatory response to, Malassezia spp. Topical therapies, including antifungal agents and low potency corticosteroids, are the mainstay of treatment but may be limited by efficacy and side effects. Few novel treatments for SD are currently being studied; however, clinical trials assessing the use of topical phosphodiesterase-4 inhibitors have been completed. Improving outcomes in SD requires recognizing patient-specific manifestations/locations of the disease, including increased awareness of how it affects people of all skin types.
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Additional Info
Unmet needs for patients with seborrheic dermatitis
J Am Acad Dermatol 2022 Dec 17;[EPub Ahead of Print], JM Jackson, A Alexis, M Zirwas, S TaylorFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Seborrheic dermatitis affects 3% to 5% of the world population and possibly more, as mild cases are often not detected. It follows a biphasic distribution, peaking in infancy and adulthood. The disease involves sebaceous glands-bearing regions, such as the scalp, mid-face, mid-trunk, and intertriginous areas. It usually presents as scaly plaques, with or without erythema. Typically, the scales have a yellowish, greasy aspect and texture. Its most common presentations are cradle cap in infants and dandruff in adults, but more extensive and severe cases are not rare. Self-limited in infants, it follows a chronic, relapsing course in adults.
Jackson and co-workers review the pathophysiology of seborrheic dermatitis. In susceptible, genetically predisposed individuals, lipid production by sebaceous glands allows the establishment on the skin surface of the yeast Malassezia furfur (the strains restricta and globosa seem more pathogenic), whose lipase break down triglycerides and cell walls, releasing irritant fatty acids and eicosanoids. These in turn initiate a cascade of inflammation through the release of cytokines by keratinocytes and T lymphocytes of Th2 and Th17 lineage. The fact that seborrheic dermatitis is more common in HIV-positive individuals and in patients with Parkinson’s disease likely reflects the role of immunosuppression in the former case, and possibly increased sebum secretion in the latter.
Recent years have seen the advent of dupilumab, an IL-4 receptor inhibitor, which has dramatically improved the treatment of severe atopic dermatitis, while the COVID-19 pandemic has brought prolonged use of occlusive face masks. These events or situations now represent new risk factors for the development of seborrheic dermatitis, as discussed by Jackson et al, who also explain why it is more common in women of African descent.
Although most cases of seborrheic dermatitis can be controlled with topical antifungals, mild corticosteroids or calcineurin inhibitors, the search for more effective and safer therapy continues. Ironically, efficacious agents are often drugs used outside of their primary indication. Such is the case with the phosphodiesterase-4 (PDE-4) inhibitor apremilast, used orally to treat psoriasis, and topical crisaborole, indicated for atopic dermatitis. These agents increase adenosine monophosphate levels and suppress proinflammatory cytokines. Case reports and small clinical trials showed beneficial effects when both drugs were used for seborrheic dermatitis.
Topical roflumilast is a PDE-4 inhibitor with far greater potency than crisaborole. Of 226 adults with seborrheic dermatitis enrolled in a randomized, double blind study, at week 8, 74% of patients in the roflumilast group reached the primary outcome (clear or almost clear) compared with 41% in the control group (P < .0001).
These interesting results will likely be followed by additional case reports and, ideally, randomized clinical trials, as newer agents, such as topical JAK inhibitors, are investigated in seborrheic dermatitis.