OBJECTIVE To provide a reference for pharmaceutical care in patients with ulcerative colitis （UC） and ankylosing spondylitis （AS） who developed pustular psoriasis induced by infliximab. METHODS Clinical pharmacists participated in the pharmaceutical care process of a patient with UC and AS who developed pustular psoriasis after using infliximab. The clinical pharmacists determined， using Naranjo’s Scale， that the correlation between the patient’s pustular psoriasis and infliximab was “likely”. Regarding the patient’s development of pustular psoriasis after using infliximab， the clinical pharmacists recommended discontinuing infliximab and switching to Upadacitinib extended-release tablets. For the patient’s skin allergic reaction after using upadacitinib， the clinical pharmacists advised continuing the use of upadacitinib and closely monitoring any potential adverse reactions during the treatment period. RESULTS The clinicians adopted the clinical pharmacists’ recommendation. Following the treatment， the patient’s symptoms were significantly alleviated， and the patient was discharged with medication. The follow-up after discharge showed that the treatment was effective and well-tolerated. CONCLUSIONS The clinical pharmacists analyzed the causal relationship between infliximab and pustular psoriasis. Through pharmaceutical care measures such as dynamic monitoring of skin lesions， evaluation of treatment responses， and optimization of drug regimens， they assisted the physicians in formulating an individualized medication plan， ensuring the safety and efficacy of the patient’s medication use.