FROM RASH TO RASH: REGIONAL DERMATOSIS IN PATIENTS ON DUPILUMAB THERAPY

Abstract

<h3>Introduction</h3> Reports of regional dermatosis associated with dupilumab use have been documented since 2019, including contact dermatitis, rosacea, seborrheic dermatitis, and sebopsoriasis¹. <h3>Case Description</h3> A 31-year-old transgender female with a lifelong history of moderate AD develops a non-pruritic flaking facial rash of 4 months duration worsening with topical steroid therapy. Patient had been on dupilumab therapy for the last 6 months. Physical examination was remarkable for flaky, yellowish scales overlying the nasolabial folds, eyebrows, and oral fissure (Figure 1). Patient was diagnosed with sebopsoriasis. <h3>Discussion</h3> There have been several case reports linking dupilumab use to regional dermatosis^1,2,3. Rheumatologic literature has linked anti-IL 17 therapies for psoriasis with increase in atopic dermatitis, postulating that inhibition of Th1 pathway increases Th2 cytokine expression and subsequent atopic flares^5,6,7. It stands to reason that the converse can be true as well. In blocking the Th2 pathway, dupilumab may simultaneously upregulate other immune pathways. While unopposed Th1 and Th17 responses may increase the likelihood to develop rosacea and psoriasis, greater indirect Th17/Th22 response may increase susceptibility to seborrheic dermatitis (SD)³. Moreover, dupilumab therapy influences an increased IgE sensitization to certain fungi (like <i>Malassezia furfur</i> in SD) and may also cause a hypersensitivity irritant reaction⁴. Further studies are required to elucidate and prove immunopathological mechanisms of regional dermatosis related to dupilumab treatment, but this case report and review postulates the potential mechanisms of immune dysregulation and changes in homeostasis which may contribute to new regional dermatosis in patients who lack prior history of such conditions.