Pustular psoriasis is a rare and severe form of psoriasis characterized by sterile pustules on an erythematous background. The disease ranges from localized to generalized forms, with the latter being particularly life-threatening and recurrent. Understanding the genetic basis of pustular psoriasis, particularly IL36RN mutations, is crucial for developing better treatments. This study aims to determine the prevalence and types of IL36RN gene mutations and their relationship with clinical and paraclinical features in patients with pustular psoriasis in Can Tho City, Vietnam. A cross-sectional study was conducted at Can Tho Dermatology Hospital involving 59 patients diagnosed with generalized pustular psoriasis (GPP) according to ERASPEN and Japanese Dermatological Association criteria. Data on demographic, clinical, and laboratory characteristics were collected. IL36RN gene mutations were identified through genomic DNA sequencing. Statistical analyses were performed to explore associations between IL36RN mutations and clinical features. The study included 59 participants, predominantly female (69.5%), with an average age of 39.12 years. A significant proportion (83.1%) had a history of psoriasis, with frequent recurrences (94.9%). The most common IL36RN mutation identified was p.Arg10ArgfsX1, present in 44.1% of patients. Other mutations included p.Pro76Leu (20.3%) and p.Arg102Trp (1.7%). Patients with IL36RN mutations were younger and had an earlier disease onset. Significant associations were found between IL36RN mutations and clinical features such as fever (OR = 11, p < 0.0001) and geographic tongue (OR = 14.67, p < 0.0001). Our study reveals a high prevalence of IL36RN mutations, particularly p.Arg10ArgfsX1, in Vietnamese pustular psoriasis patients, strongly associating these mutations with clinical features like fever and geographic tongue.