This case report presents a 53-year-old woman with a previous diagnosis of episodic migraine without aura and menstrually related migraine without aura. She had long avoided head accessories, such as glasses and headbands, due to the pain they caused. Approximately one year ago, upon starting water-based exercise requiring the use of swim caps, a new headache type became evident, ultimately leading to the diagnosis of external-pressure headache (EPH). The characteristics of the headaches varied depending on the type of swim cap used: a fabric cap with an elastic band caused mild, localized discomfort that resolved immediately upon removal, while a silicone cap triggered more severe, holocranial pain accompanied by migrainous features such as photophobia, phonophobia, and difficulty concentrating. These episodes, likely influenced by her pre-existing migraine diagnosis, persisted even after removing the cap and occasionally required the use of analgesics. This case underscores the clinical relevance of EPH, highlighting the importance of patient education and ergonomic adaptations to minimize triggers, as well as the need to recognize EPH as a distinct headache subtype. This article will further explore diagnosis, pathophysiology, clinical presentation, and treatment strategies for EPH, offering practical insights into its management in both recreational and occupational settings.