This case report describes a 34-year-old man with a history of adult-onset PFAPA (Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis), von Willebrand disease and Factor XI deficiency who experienced an anaphalactic allergic reaction to Hexakapron.Case reportOriginal and rareThe rarity of such reactions presents a diagnostic challenge, as there are no widely accepted, specific tests for TXA-induced allergies. Treatment of these patients in case of bleeding from any cause raises a therapeutic dilemma, to date the most common and widely used anti hemorrhagic medication remains TXA. In this patient it is worth to consider whether the co-morbidity of adult-onset PFAPA, a rare rheumatologic presentationHexakapron (tranexamic acid – TXA) is a widely used antifibrinolytic agent that is generally well-tolerated, with allergic reactions being uncommon. Severe hypersensitivity responses, such as anaphylaxis, are exceedingly rare, making the occurrence in this case particularly noteworthy.  The rarity of such reactions presents a diagnostic challenge, as there are no widely accepted, specific tests for TXA-induced allergies. Skin testing may help confirm the diagnosis, although its sensitivity and specificity are not well-established, and drug provocation tests may sometimes be required to confirm the connection between the drug and the allergic reaction but carries a risk of invoking a life threatening event.  Treatment of these patients in case of bleeding from any cause raises a therapeutic dilemma, to date the most common and widely used anti hemorrhagic medication remains TXA. As the response is not dose dependent and can manifest with even nominal exposure, as in this patient during allergy testing, it remains a challenge to manage bleeding.This case highlights a challenge and treatment dilemma in this patient and others like him who on the one hand have a bleeding disorder and are prone to bleeding, but are severely allergic to Hexacpron on the other hand limiting the available treatment course in case of bleeding from any cause. In conclusion, while the incidence of allergic reactions to Hexakapron remains low, continued awareness, research, and case reporting are critical for advancing our understanding and ensuring patient safety.