We report a patient with recurrent isolated Hornersyndrome without headache, rhinorrhea, ocular or nasalcongestion, tearing, or any abnormalities on brain and neckimaging.A 28-year-old male resident physician reported a 2-week history of episodic right upper lid ptosis and miosis.During the first episode, the ptosis and miosis resolvedwithin 30 minutes, and there was no associated headache,eye pain, tearing, nasal congestion, or rhinorrhea. Theepisode was witnessed by his fellow residents and anattending physician during morning report, and hewas senttotheemergencyroomforevaluation.However,bythetimehe arrived, the episode had resolved. For the next 2 weeks,he had nearly daily recurrences of the same symptoms. Theduration of the episodes ranged from 10 minutes to 11hours, with an average of 30 to 45 minutes. During one ofthe episodes, he ran up several flights of stairs and notedthat he had anhydrosis of the right side of his forehead.His past medical andsurgical history were unremark-able. He denied head or neck trauma, neck pain, arm pain,migraine or cluster headache, or cigarette smoking. Hismother had migraine headache, but there was no familyhistory of cluster headache.On our initial neuro-ophthalmologic examination,best-corrected visual acuity was 20/20 in both eyes. Eyemovements and alignment were normal, and confrontationvisual fields were full. Pupils were 5 mm, round, andreactive to light in both eyes without an afferent defect.Cranial nerve examination was normal, as was the rest ofthe ophthalmologic examination. Results of MRI of thehead and neck with contrast, MRA of the neck, and chestx-ray with apical and lordotic views were normal.Examinationduringa recurrence 1 week later, after hehad run over from the hospital, showed 2 mm of right upperlid ptosis. The right pupil was 4 mm and the left pupil was6.5 mm in darkness, both constricting normally to brightlight. The ptosis and anisocoria resolved completely within5 minutes of his arrival and 30 minutes from onset. Topicalcocaine testing could therefore not be performed. He re-ported resolutionof theseepisodeswithin 4weeks ofonset,and he has had neither a recurrence of the episodes nor thedevelopment of cluster headaches in 4 years of follow-up.Ourpatient’sfindingsarehighlysuggestiveofaninter-mittent Horner syndrome, and his report of anhydrosis lim-itedtotheforeheadissuggestive,althoughnotdiagnostic,ofapostganglionicetiology.Cervicalcordlesions(1,2),carotidartery lesions (3,4), and cluster headache (5,6) have beenassociatedwithcasesof intermittentHornersyndrome.Thenormal MRI and MRA results in our patient effectivelyruled out cervical or carotid artery lesions as culprits.Cluster headache sine headache was first reported bySalvesen (5), who described a patient suffering from dailyattacks of Horner syndrome and nasal congestion but nopain.Althoughour patientandthepatientofSalvesensharea similar pattern of painless, intermittent Horner syndrome,normal neuroimaging studies, and normal examinationsbetween episodes, the unique aspect of our case is theabsence of associated parasympathetic symptoms such asrhinorrhea, nasal stuffiness, or lacrimation. Havalius (7)reportedfivepatientsranginginagefrom2to20yearswithconstant ptosis and miosis for years before the onset of anipsilateral cluster headache.Hedocumentedthefindingsbyphotographs or patient reports, and therewere no reports ofan episodic Horner syndrome similar to that noted in ourpatient. Although the exact mechanism of the Horner syn-drome in our patient is unknown, we believe it representsa variant of cluster headache sine headache.Marjorie A. Murphy, MDLawrence C. Hou, MDDepartment of OphthalmologyRhode Island Hospital and Brown Medical SchoolProvidence, Rhode IslandMargieMurphy@cox.netREFERENCES