Unexplained cough: it is time to rule out Sjogren's syndrome

Sjogren's syndrome is associated with chronic cough, but sicca symptoms are missing from cough evaluation guidelines. We evaluated patients with unexplained cough for undiagnosed Sjogren's syndrome. Patients referred to our pulmonary clinic (Sheba Medical Center, 2009 to 2012) with unexplained cough and concomitant dry eyes were selected for evaluation. Unexplained cough was defined as chronic cough of unknown etiology despite algorithm-based evaluation and treatment. Patients were evaluated in a dedicated clinic by a pulmonologist, rheumatologist, and ophthalmologist specializing in autoimmune disease. Patients completed the Leicester Cough Questionnaire, spirometry, antibody testing for anti Ro/La, ophthalmologic examination with visual acuity, eyelid, ocular surface fluorescein staining, tear break-up time and Schirmer's test, full slit lamp, and fundus examinations. Four-year follow-up was conducted by telephone questionnaire. We identified 24 patients among which 22 (21 females) agreed for evaluation. Eight patients (36%), seven initially, and one during follow-up were diagnosed with Sjogren's syndrome (SS) (six secondary and two primary SS). At 4-year follow-up, cough tended to persist and improve in only 37% with SS. These include 2 (Scl and RA) who received rituximab and 1 (stage 1 sarcoidosis) with spontaneous improvement. In contrast, cough improved in most (64%) patients without SS; the majority (eight/nine) report intensified disease-specific treatment (five allergic and three GERD). We describe patients in whom unexplained chronic cough was associated with dry eyes. Focused workup revealed undiagnosed Sjogren's syndrome in 36%. Dry eyes, with or without SS, is under-recognized and should be added to diagnostic algorithms for unexplained cough.