Abstract

We report the first case of occupational asthma to colophony free gel flux predominantly containing dodecanedioic acid. The patient worked as an electronics instructor from 1999 where he initially used solder wire and a separate flux (both colophony). In 2002 he changed to a colophony-free solder wire (predominantly palmitic acid) and a separate gel flux. In 2004 he developed work-related stuffy nose and dyspnoea. This became worse in 2005 when he woke twice a night and had a blocked nose, wheeze and sputum for the first 2 hours after waking. Serial peak expiratory flow records confirmed occupational asthma (Oasys score 3). His exhaled nitric oxide while exposed was 14.3ppb (Aerocrine Niox). He was admitted for specific bronchial challenge testing to both solder wires and fluxes. He melted approximately 5 metres of solder wire (using an iron heated to 370°C) spread over 3 challenges totalling 70 minutes. For the fluxes, he dipped the soldering iron into the flux approximately every 10 seconds, letting it fume into the challenge chamber after each insertion. For the colophony flux, he did this over 3 challenges totalling 17 minutes, and for only 8 minutes when using the colophony-free gel flux. He was negative to colophony wire/flux and wire containing predominantly palmitic acid, but positive to gel flux containing predominantly dodecanedioic acid, falling by a maximum of 23% from baseline. His methacholine reactivity was >4800 Dg methacholine (Yan method) pre challenge, becoming measurable post challenge at 3490 ug

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