More than 200 kinds of occupational allergens are known to cause occupational asthma. But there has been no case report of occupational asthma caused by herb materials except one case reported by Moon et al in 1986 in Korea. Licorice is one of
the
oldest traditional chinese medicines and is used as a tonic, antiphlogistic, mucolytic, expectorant, and an analgesic for the treatment of gastrointestinal and respiratory disorders and also to alleviate the toxicity of some other drugs.
We report a case of occupational asthma caused by licorice.
A 34 year-old male patient came to the clinic because of cough, dyspnea and wheexing which had developed one month ago. He had worked at a herb drug store for 3 years. His symptoms used to be worsened during and shortly after his work and
subsided
several hours after rest. When he visited the clinic, he had no such symptoms and revealed no abnormality on physical examinations. At that time peripheral blood eosinophil count was 590/mm3, total IgE (PRIST) was 770IU/ml. Radiologic findings of
chest
and paranasal sinus were normal. Skin prick test with common inhalant allergens revealed positivities to various allergens and licorice extract. He showed a bronchial hyperresponsiveness on methacholine bronchoprovocation test, which increased 24
hours
after allergen bronchial provocation with licorice powder and extract. He showed early asthmatic responses to allergen bronchial provocations with licorice powder and extract.
Licorice is constituted by triterpenoid, flavonoid and isoflavonoid derivatives. The structures of these constituents are almost low molecular chemicals. In this case the patient showed a positive bronchial provocation test to licorice powder and
licorice extract and a positive skin prick test to licorice extract. Thus it is suggested that pathogenic mechanism of licorice induced asthma may be an IgE-mediated allergic reaction. But further studies will be necessory to evaluate exact
pathogenesis
of licorice induced asthma.
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