Atopic dermatitis and psoriasis are two chronic inflammatory skin diseases with distinct immune mechanisms, primarily driven by Th2-type inflammation and Th1/Th17 pathways, respectively. However, some patients may simultaneously or sequentially exhibit overlapping phenotypes of atopic dermatitis and psoriasis (psoriasis-atopic dermatitis overlap, PAO), characterized by the coexistence of scaly erythema and eczematous lesions. Currently, the nomenclature, diagnostic criteria, and pathogenesis of PAO remain unclear, and its incidence is increasing due to the widespread use of targeted therapies. The diagnosis of PAO requires an integrated assessment of clinical features, histopathological findings, and biomarker profiles, while treatment necessitates a balance between immune modulation and individualized strategies. This article summarizes the characteristic manifestations of and genetic-immune interactions involved in PAO based on clinical practice, and explores diagnostic challenges and therapeutic options to address this complex and increasingly prominent clinical issue.

Objective:To analyze the clinical characteristics between patients with psoriasis-atopic dermatitis overlap (PAO) and those with psoriasis vulgaris (PSO), and to enhance the understanding of the diagnosis and treatment of this overlap phenotype.Methods:A retrospective exploratory study was conducted on clinical data from patients who were diagnosed with PAO or PSO at the Department of Dermatology, Southwest Hospital, Army Medical University between January 2018 and June 2025. Clinical characteristics, laboratory examination results, comorbidities, and treatment regimens were compared between the two groups. Categorical data were compared using the chi-square test or Fisher's exact test; for non-normally distributed measurement data, intergroup comparisons were conducted using the Mann-Whitney U test. Results:A total of 103 PSO patients and 13 PAO patients were included. Patients in the PAO group were older than those in the PSO group ( M [ Q1, Q3]:63.00 [54.00, 71.50] years vs. 50.00 [38.00, 61.00] years; Z = 2.75, P = 0.006]. No significant differences were found between the two groups in terms of gender distribution, body mass index, disease duration, personal or family history of atopic diseases (all P > 0.05). Skin lesions involved the whole body in both PAO and PSO groups, with the trunk and limbs being commonly affected sites, and no significant difference in the lesion distribution was observed ( P > 0.05). Compared with the PSO group, the PAO group had fewer plaque lesions (5/13 [38.5%] vs. 70/103 [68.0%]), but more eczematous changes such as erosions and exudation, as well as scratches and crusts due to pruritus (all P < 0.05). Laboratory tests revealed that the PAO group showed increased peripheral blood neutrophil counts, eosinophil counts, serum IgE levels, eosinophil-to-lymphocyte ratios (ELRs), and neutrophil-to-lymphocyte ratios (NLRs) compared with the PSO group (all P < 0.05) ; moreover, the proportions of patients with elevated eosinophil counts (5/13 [38.5%] vs. 8/103 [7.8%], P < 0.001) and those with elevated serum IgE levels (10/13 [76.9%] vs. 39/103 [37.9%], P = 0.014) were significantly higher in the PAO group than in the PSO group. Compared with the PSO group, the PAO group had a higher overall comorbidity rate (11/13 [84.6%] vs. 52/103 [50.5%], P = 0.035), including a higher prevalence of hypertension. Regarding topical treatments, no significant differences were found in the use frequency of topical glucocorticoids (96 [93.2%] vs. 11 [84.6%]) or vitamin D3 analogs between the two groups (both P > 0.05) ; for systemic treatments, immunosuppressants such as cyclosporine (4/13 [30.8%] vs. 2/103 [1.9%], P = 0.001) and Tripterygium wilfordii (4/13 [30.8%] vs. 7/103 [6.8%], P = 0.021) were more commonly used in the PAO group compared with the PSO group; for targeted therapies, the PSO group received interleukin (IL) -17A inhibitors (13 cases, 12.6%), IL-23 inhibitors (4 cases, 3.9%), or tumor necrosis factor-α inhibitors (5 cases, 4.9%), while the PAO group received Janus kinase inhibitors (2 cases, 15.4%) or an IL-23 inhibitor (1 case, 7.7%) . Conclusions:PAO exhibited characteristics of both PSO and atopic dermatitis, with distinct differences in skin manifestations, laboratory findings, and treatment approaches compared with PSO. Topical glucocorticoids were the primary topical treatment for PAO, while systemic treatment was centered on immunosuppressants, highlighting the need for personalized treatment strategies.

Atopic dermatitis and psoriasis are two chronic inflammatory skin diseases with distinct immune mechanisms, primarily driven by Th2-type inflammation and Th1/Th17 pathways, respectively. However, some patients may simultaneously or sequentially exhibit overlapping phenotypes of atopic dermatitis and psoriasis (psoriasis-atopic dermatitis overlap, PAO), characterized by the coexistence of scaly erythema and eczematous lesions. Currently, the nomenclature, diagnostic criteria, and pathogenesis of PAO remain unclear, and its incidence is increasing due to the widespread use of targeted therapies. The diagnosis of PAO requires an integrated assessment of clinical features, histopathological findings, and biomarker profiles, while treatment necessitates a balance between immune modulation and individualized strategies. This article summarizes the characteristic manifestations of and genetic-immune interactions involved in PAO based on clinical practice, and explores diagnostic challenges and therapeutic options to address this complex and increasingly prominent clinical issue.

Objective:To analyze the clinical characteristics between patients with psoriasis-atopic dermatitis overlap (PAO) and those with psoriasis vulgaris (PSO), and to enhance the understanding of the diagnosis and treatment of this overlap phenotype.Methods:A retrospective exploratory study was conducted on clinical data from patients who were diagnosed with PAO or PSO at the Department of Dermatology, Southwest Hospital, Army Medical University between January 2018 and June 2025. Clinical characteristics, laboratory examination results, comorbidities, and treatment regimens were compared between the two groups. Categorical data were compared using the chi-square test or Fisher's exact test; for non-normally distributed measurement data, intergroup comparisons were conducted using the Mann-Whitney U test. Results:A total of 103 PSO patients and 13 PAO patients were included. Patients in the PAO group were older than those in the PSO group ( M [ Q1, Q3]:63.00 [54.00, 71.50] years vs. 50.00 [38.00, 61.00] years; Z = 2.75, P = 0.006]. No significant differences were found between the two groups in terms of gender distribution, body mass index, disease duration, personal or family history of atopic diseases (all P > 0.05). Skin lesions involved the whole body in both PAO and PSO groups, with the trunk and limbs being commonly affected sites, and no significant difference in the lesion distribution was observed ( P > 0.05). Compared with the PSO group, the PAO group had fewer plaque lesions (5/13 [38.5%] vs. 70/103 [68.0%]), but more eczematous changes such as erosions and exudation, as well as scratches and crusts due to pruritus (all P < 0.05). Laboratory tests revealed that the PAO group showed increased peripheral blood neutrophil counts, eosinophil counts, serum IgE levels, eosinophil-to-lymphocyte ratios (ELRs), and neutrophil-to-lymphocyte ratios (NLRs) compared with the PSO group (all P < 0.05) ; moreover, the proportions of patients with elevated eosinophil counts (5/13 [38.5%] vs. 8/103 [7.8%], P < 0.001) and those with elevated serum IgE levels (10/13 [76.9%] vs. 39/103 [37.9%], P = 0.014) were significantly higher in the PAO group than in the PSO group. Compared with the PSO group, the PAO group had a higher overall comorbidity rate (11/13 [84.6%] vs. 52/103 [50.5%], P = 0.035), including a higher prevalence of hypertension. Regarding topical treatments, no significant differences were found in the use frequency of topical glucocorticoids (96 [93.2%] vs. 11 [84.6%]) or vitamin D3 analogs between the two groups (both P > 0.05) ; for systemic treatments, immunosuppressants such as cyclosporine (4/13 [30.8%] vs. 2/103 [1.9%], P = 0.001) and Tripterygium wilfordii (4/13 [30.8%] vs. 7/103 [6.8%], P = 0.021) were more commonly used in the PAO group compared with the PSO group; for targeted therapies, the PSO group received interleukin (IL) -17A inhibitors (13 cases, 12.6%), IL-23 inhibitors (4 cases, 3.9%), or tumor necrosis factor-α inhibitors (5 cases, 4.9%), while the PAO group received Janus kinase inhibitors (2 cases, 15.4%) or an IL-23 inhibitor (1 case, 7.7%) . Conclusions:PAO exhibited characteristics of both PSO and atopic dermatitis, with distinct differences in skin manifestations, laboratory findings, and treatment approaches compared with PSO. Topical glucocorticoids were the primary topical treatment for PAO, while systemic treatment was centered on immunosuppressants, highlighting the need for personalized treatment strategies.