Avoidance therapy in reactive dye-induced occupational asthma: long-term follow-up.
BACKGROUND
Previous studies reported that early diagnosis and avoidance therapy are the most important factors for prevention of permanent lung impairment; however, few studies have evaluated the long-term prognosis of reactive dye-induced occupational asthma (RD-OA).


OBJECTIVE
To evaluate the long-term outcomes of RD-OA.


METHODS
Methacholine airway hyperresponsiveness (AHR) and lung functions were evaluated and compared in 26 patients with RD-OA at the time of diagnosis and after complete avoidance of the causative agents. Patients with continued (n = 13) or remitted (n = 6) AHR were further monitored for up to a mean +/- SD of 8.7 +/- 1.8 years.


RESULTS
The AHR resolved in 10 (38%) of 26 patients a mean +/- SD of 2.2 +/- 1.3 years after complete avoidance of RDs; however, prebronchodilator forced expiratory volume in 1 second (FEV1) values were not different. Levels of IgE specific to the RD-human serum albumin complex were markedly decreased at first follow-up in 5 RD-atopic patients from whom paired serum samples were compared (P = .02). The AHR disappeared in an additional 5 patients and improved in 4 by the second follow-up. The FEV1 values also improved compared with diagnosis and first follow-up levels. Favorable prognosis was associated with early diagnosis of RD-OA and complete avoidance of the causative agent. No association was found with smoking history, latent periods, the presence of RD specific IgE, baseline provocation concentration that caused a decrease in FEV1 of 20%, or FEV1.


CONCLUSIONS
Early diagnosis and avoidance therapy are the most important prognostic factors in RD-OA. The AHR and lung function of patients with RD-OA can sometimes be recovered steadily and slowly through avoidance measures.
Park
Jung-Won
JW
Institute of Allergy, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
Yang
Joo-Young
JY
Kim
Cheol-Woo
CW
Kim
Kyu-Sang
KS
Hong
Chein-Soo
CS
D001249:Asthma / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control*; D004396:Coloring Agents / Q000009:adverse effects*; D005500:Follow-Up Studies; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007723:Korea; D016210:Methacholine Chloride; D009784:Occupational Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control*; D011379:Prognosis; D040242:Risk Reduction Behavior; D016896:Treatment Outcome
D004396:Coloring Agents; D016210:Methacholine Chloride; D007073:Immunoglobulin E