Contact dermatitis due to topical traditional Chinese medication

In 1997, Dr. Yung Hian Leow reviewed adverse skin reactions to topical traditional Chinese medications (TTCMs), including allergic and irritant contact dermatitis, and contact urticaria. The review highlighted the challenges in diagnosing these reactions due to the secretive nature of TTCM formulations, which complicates patch testing. Specific cases of allergic reactions to products like Yunnan Paiyao and 101 Hair regrowth liniment were discussed, as well as irritant reactions to Lu-Shen-Wan and Blackman oil, and urticaria from Shexianghugu plaster. The paper concluded that standard patch testing procedures should be followed, with additional tests for certain substances when relevant, and called for collaboration with traditional Chinese medicine practitioners to identify TTCM constituents. It also recommended reporting cases of contact dermatitis to raise awareness of TTCM side effects and suggested chemical analysis to identify allergens.