D3.435 - “Looking Twice in Atopic Dermatitis Therapy: Pruritus Is Not Always the Same, and Eczema Is Not Always Atopic Dermatitis”

Introduction:Atopic dermatitis (AD) is a chronic, non-contagious inflammatory skin disease characterized by xerosis, eczematous lesions, and severe pruritus, leading to a considerable disease burden. It usually begins in childhood and is often associated with other atopic conditions, such as bronchial asthma or allergic rhinoconjunctivitis. Immunologically, AD is dominated by Th2-mediated inflammation with increased expression of IL-4,-5, and IL-13, resulting in eosinophilia and elevated IgE levels. IL-31 plays a key role in the pathogenesis of pruritus and is also elevated in other pruritic diseases, including T-cell lymphoma.

Case Presentation:A 65-year-old man with AD, allergic rhinoconjunctivitis, and a high disease burden was presented. Relevant comorbidities included T-cell non-Hodgkin lymphoma (diagnosed in 2023) and recurrent ocular infections. Previous treatment with class IV topical corticosteroids and UVB 311 phototherapy was ineffective. At presentation, SCORAD (Scoring Atopic Dermatitis; max. 103) was 68 and DLQI (Dermatology Life Quality Index; max. 30) was 17.Due to insufficient response, systemic treatment with dupilumab was initiated, resulting in marked clinical improvement. However, recurrent ocular infections, including perforated corneal ulcers and HSV-1 reactivations, occurred and led to treatment discontinuation. Subsequent therapy with lebrikizumab was also stopped because of recurrent ocular complications, ultimately necessitating corneal transplantation. Given persistent severe pruritus, treatment with nemolizumab was initiated. This resulted in a rapid reduction of pruritus (NRS 10 to 2 within 2 days) and an improvement in RECAP (Recap of Atopic Eczema; max. 28) from 19 to 8 after one month. However, complete skin clearance was not achieved (SCORAD 68 to 47). Persistent erythema and scaling prompted further diagnostics, revealing a cutaneous infection with Trichophyton rubrum. Targeted antifungal therapy led to significant improvement (SCORAD 47 to 26).

Conclusion:This case emphasizes the importance of critically reassessing chronic pruritic and eczematous skin lesions in patients with established AD. Concomitant conditions, such as fungal infections, may substantially contribute to disease severity and should always be excluded. Furthermore, malignant diseases, including cutaneous T-cell lymphomas or epithelial skin tumors, may present with similar clinical features and must be considered in the diagnostic workup. In this case, earlier recognition of the mycosis could have substantially reduced the patient’s disease burden.