“One nostril keeps blocking and bleeding — just hay fever, surely?”

The one-sided rule: UNILATERAL persistent nasal obstruction with blood-stained discharge or recurrent unilateral epistaxis is a RED FLAG (possible sinonasal or nasopharyngeal tumour) and must NOT be treated as "hay fever" — benign allergic rhinitis is typically BILATERAL, seasonal, with sneezing/itch and clear discharge. Nasopharyngeal carcinoma classically presents with a NECK LUMP (often first), UNILATERAL serous otitis media/blocked ear (Eustachian obstruction), blood-stained nasal discharge and cranial-nerve signs, with higher risk in people of Southern Chinese/Southeast Asian origin — so elicit these red flags and the ethnicity-related risk, examine the nose/ears/neck (a unilateral middle-ear effusion in an adult and an unexplained neck lump each warrant urgent referral), and refer urgently to ENT for nasendoscopy rather than trialling allergy treatment for a one-sided problem. Keep the benign differential (polyp, foreign body, deviated septum) in mind but do not let it justify allergy treatment without examination/referral. The hidden agenda is the "hay fever" misconception plus avoidance masking a noticed neck lump and quiet fear; don’t accept the framing, surface the fear, reassure proportionately, and refer. Unilateral persistent nasal obstruction/epistaxis can also be benign (e.g. a polyp, foreign body, deviated septum), but the one-sided pattern mandates examination and ENT referral to exclude tumour — you cannot reassure it away as allergy. NPC caught earlier has better outcomes.