Abstract

A recent consensus statement has highlighted the increased risk of developing asthma after exposure to workplace and domestic cleaning products. Specific cleaning agents, such as benzylalkonium chloride, have been recognized as causes of occupational asthma by sensitization and now comprise a significant burden of work-related asthma. European Respiratory Society guidelines recommend that sensitizer-induced occupational asthma should be diagnosed by identifying the workplace as the cause and confirming sensitization to an asthmagen by specific inhalation challenge (SIC) in the absence of any available specific IgE tests. We present the first case of occupational asthma caused by the biocide triclosan, commonly used in cleaning and personal care products.
A 26-year-old woman presented with a 7-month history of cough, wheeze, and chest tightness that became progressively worse throughout the working week and better on days away from work. She required treatment with a symbicort inhaler, 400/12 mg twice a day. She had childhood eczema and asthma and previous anaphylaxis caused by peanuts at the age of 16 years. She had been employed as a nursery nurse for 12 months, caring for 30 children aged 2 to 3 years. Her work tasks involved mopping using 5% trisodium nitrilotriacetate (Versatile) cleaner daily and cleaning tables using liquid cleaner containing 0.05% triclosan (Antibac; pH 7.0). She used latex gloves and a gel containing 70% ethanol for hand cleaning (Proform, Gompels Healthcare Ltd, Melksham, United Kingdom). Clinical examination and chest radiographic findings were unremarkable, and spirometry results were normal (forced expiratory volume in 1 second [FEV1], 3.55 L [103% predicted]; forced vital capacity [FVC], 4.05 L [103% predicted]). Total IgE level was less than 2 kU/L, the results of testing for serum specific IgE to latex were negative, and the eosinophil count was 0.02
109/L. Two-hourly peak flow measurements made at home and work for 4 weeks were analyzed using the OASYS computer program. The OASYS score was 3.5 and the area between the curves score was 27 L/min per hour, both confirming a significant work effect. The patient underwent SIC testing, with negative control challenges to both the hand gel and 5% trisodium nitrilotriacetate cleaner (diluted to 1:100). She was subsequently exposed to triclosan surface cleaner diluted to 1:60 with water by painting on cardboard for a total of 30 minutes and experienced a sustained, immediate decrease in FEV1 by 24% from a baseline of 3.42 L (Fig 1), consistent with sensitization.4 There was no clinically significant change in fractional exhaled nitric oxide (FeNO) (pre-SIC, 9 ppb; 24 hours after SIC, 9 ppb); all measurements were performed according to European Respiratory Society/American Thoracic Society guidelines. Nonspecific bronchial reactivity (NSBR) by methacholine challenge, using the Jaeger dosimeter, was normal (provocation dosage that caused a decrease in FEV1 of 20%, >2.1 mg) before and 24 hours after SIC. After the diagnosis of occupational asthma, the patient remained employed in the same role, the liquid cleaner containing 0.05% triclosan (Antibac) cleaner having been substituted in the workplace. She remained relatively symptom free with 400/12 mg of inhaled symbicort twice a day, and spirometry performed 24 months after diagnosis revealed an FEV1 of 3.24 L (96% predicted) and an FVC of 3.87 L (100% predicted). A further serial peak expiratory flow analysis at this time revealed an OASYS score of 2.5 and an ABC score of 2 L/min per hour.
Triclosan (2,4,4’-trichloro-2’-hydroxydiphenyl ether)

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