D2.149 - Occupational asthma in a tea-packaging worker: a case report

Background: Tea is widely consumed worldwide, and Türkiye’s Black Sea region is a major production area. Although occupational asthma from tea dust has been described, IgE-mediated sensitization is rarely reported and the allergenic profile remains unclear.

Method: The case was evaluated at a university hospital in Türkiye’s Black Sea region. Routine aeroallergen SPT includes house dust mites, molds, animal danders, pollens, and latex. For the specific bronchial provocation test, baseline spirometry was performed, followed by 30 minutes of manual exposure to dry black tea dust. After a 15-minute rest in clean air, spirometry was repeated. The test was terminated if ≥20% fall in FEV1 or significant symptoms occurred. The challenge was conducted in a well-ventilated room with continuous clinical monitoring.

Results: A 32-year-old male presented with a 3-year history of dyspnea, wheezing, nasal itching, rhinorrhea, and sneezing, worsening at work and improving away from exposure. He had a 10 pack-year smoking history, and had worked for 7 years in a tea-processing factory packaging dry black tea dust. Mild rhinitis began after 2 years of exposure and gradually progressed to asthma, for which he had been treated with ICS/LABA, montelukast, and levocetirizine. He presented one week after leaving work with persistent symptoms (ACT 17). Baseline spirometry showed mild obstruction (FEV1/FVC 79%, FEV1 77%). SPT and serum specific IgE were negative. Prick-to-prick testing was positive with fresh tea leaf (16×8 mm), weakly positive with diluted tea dust (4×4 mm), and negative with brewed tea.

By the second week after leaving work, symptoms had markedly improved and spirometry normalized, allowing discontinuation of controller therapy. Workplace PEF monitoring was not feasible. After 1.5 months without exposure or treatment, symptoms fully resolved (ACT 25) and spirometry remained normal (FEV1/FVC 85%, FEV1 89%). The specific inhalation challenge produced a 34% fall in FEV1 with upper and lower airway symptoms (Figure 1). He tolerated drinking black tea, supporting preserved oral tolerance. The chronological clinical course is shown in Figure 2.

Conclusion: This case demonstrates a dissociation between inhalation sensitization and oral tolerance. The contrasting prick-to-prick responses—positive to raw tea particles but negative to brewed tea—suggest heat-labile allergens, providing a plausible explanation for preserved oral tolerance despite significant respiratory sensitization.