Background: Psoriasis is a persistent systemic inflammatory condition mediated by the interleukin (IL)-23/IL-17 signaling pathway. Existing murine models, including imiquimod (IMQ)-applied wild-type (WT) mice, may not reflect chronicity and systemic comorbidities of psoriasis, particularly gut-related manifestations linked to the gut–skin axis. Objective: To establish a murine model that more accurately reflects chronic psoriasis, its systemic comorbidities, and associated gut environment alterations. Methods: C57BL/6 IL-10-deficient (IL-10 knockout [KO]) and WT mice received topical IMQ or vehicle for 6 weeks. Subsequently, tissue samples from skin, colon, joints, kidneys, liver, abdominal aortas, lymph nodes, and spleens, as well as fecal and blood samples, were collected for histopathologic, immunologic, gut environment analysis. Results: IMQ-treated IL-10 KO mice developed prolonged psoriatic inflammatory responses with increased epidermal thickness and higher infiltration of CD45+, myeloperoxidase+, and IL-17+ cells. They also exhibited early-onset, severe colitis with marked weight loss, shortened colon length, and elevated colitis severity scores. While IMQ induced systemic inflammation in multiple organs, IL-10 KO mice did not show more severe joint, liver, or kidney involvement than WT mice. Elevated serum tumor necrosis factor alpha and plasminogen activator inhibitor-1 levels, increased heart/body weight ratio, enhanced gut permeability, and distinct gut microbiota profiles were observed in IL-10 KO mice. Conclusion The 6-week IMQ-applied IL-10 KO model may better reflect chronic and severe psoriasis with gut-related comorbidities, offering a valuable platform to investigate the gut–skin axis.

BACKGROUND: Pincer nail is a deformity of the nail that is characterized by the transverse overcurvature of the nail plate. Both conservative and surgical treatments can be used to treat pincer nail. However, there are no reports regarding non-surgical, laser treatment of pincer nail. OBJECTIVE: To evaluate the treatment outcomes and adverse events of CO₂ fractional laser and topical agent combination therapy on pincer nail. METHODS: Eleven pincer nails (all great toenails) were treated with a CO₂ fractional laser. An antifungal agent (in case of co-existing onychomycosis) or 20% urea cream was applied to the toenails. The effect of the treatment was measured by evaluating the difference in the width index, height index, and nail angle before and after treatment. Changes in pain levels were also evaluated. All adverse events and recurrences were observed until the last follow-up visit. RESULTS: The mean number of laser treatments was 2.27 and the mean follow-up period was 18.36 weeks after the last treatment. All 3 measured indices changed significantly after the treatment. The width index increased by 0.16 (p=0.0016), the height index decreased by 1.89 (p=0.008), and the nail angle increased by 29.60° (p=0.005). The pain was reduced in all cases. There were no serious adverse events. CONCLUSION The combination of CO₂ fractional laser therapy and topical application is an effective and tolerable treatment for pincer nail. Larger studies with long-term observations are needed to confirm this result.