# Shedding Light on FIRE Syndrome: An Overview of a Novel Condition in Eosinophilic Esophagitis
## 3 Clinical Presentation of FIRE Syndrome  
FIRE syndrome manifests with atypical complaints among EoE patients. It is characterized by intense, retrosternal discomfort or pain that occurs rapidly and reproducibly after ingestion of specific foods or beverages [16; 19]. Unlike solid food dysphagia in EoE, these manifestations are instead described as a tightening or pressure sensation in the mid-sternum, a choking sensation that could be accompanied by anxiety, chest pain, or heartburn [16; 17]. The series of patients surveyed by [PERSON] et al. reported FIRE characteristics such as narrowing, pressure, burning, choking, locking, cramps, or swelling; 33% of patients also reported anxiety caused by these sensations [16]. The symptoms have a remarkably sudden onset, typically developing within the first 5 min following exposure to the trigger, with interindividual variations ranging from 1 to 60 min. This abrupt development of symptoms is correlated with an impressive intensity, most often rated 7 or higher on a 1-10 visual analog scale (VAS) by patients. Due to the severity of symptoms, many patients actively avoid exposure to identified triggers [16; 17; 18; 19]. Another striking feature is the limited duration of symptoms. A FIRE syndrome episode may last between a few minutes and approximately 6 h. Data show that 72.4% of patients reported by [PERSON] et al. had symptoms lasting less than 30 min, almost all becoming symptom-free in under 2 h (96.5%) [16; 17; 18; 19]. Interestingly, even if the symptoms subside in a relatively short time, there are, however, patients that report experiencing lasting dysphagia in the following days after an episode [16]. In EoE patients, symptoms suggestive of FIRE syndrome or pollen-food allergy syndrome (PFAS) may coexist or occasionally overlap, both with one another but also with the typical symptoms of EoE. Given this potential clinical crossover, a careful clinical distinction among these entities is essential to formulate the precise diagnostic [16; 19; 22; 23]. The symptoms in EoE are triggered by solid, fibrous food ingestion, the size of the food being of importance as well [24]. This serves as the rationale for the adaptive eating behaviors observed in these patients [25]. Unlike them, FIRE syndrome patients present with symptoms triggered by even the smallest serving of the triggering food, and compensatory eating habits do not alleviate esophageal discomfort. An intriguing aspect of FIRE syndrome is that symptoms can be triggered by beverages such as milk, beer, or wine, a characteristic that is not observed in EoE [16; 17; 18; 19]. Consequently, the absence of symptom relief through modifications of serving size and food texture, along with ubiquitous trigger avoidance, can be distinctive features to help identify FIRE syndrome in EoE patients [16; 17; 18; 19]. PFAS is a frequent comorbidity in EoE patients and was reported in approximately one-third of EoE patients, commonly triggered by fresh (raw) fruits or vegetables, including apples (21.1%), carrots (15.5%), and peaches (15.5%) [26]. Like in FIRE syndrome, PFAS symptoms appear immediately after ingestion of food triggers. However, the two conditions vary considerably in the location and quality of symptoms. PFAS typically causes itching, tingling, or mild swelling usually limited to the orophynx, while FIRE syndrome is characterized by intense retrosternal discomfort, such as pressure or pain, often described by patients as \"esophageal constriction\" [16; 27]. The two conditions may share the same triggers; however, FIRE syndrome may also be triggered by liquids (such as vinegar, milk, or wine), a feature that is not observed in PFAS, where the main elicitors are raw plant-based foods [16; 19]. Both FIRE syndrome and PFAS can coexist in the same patient, as reported in 75% of cases in [PERSON] et al. 's series of adult patients [17]. Patients seem to be able to clearly differentiate between the two entities, based on symptom quality and location [17].