Gan Qi

Retrospective review of 31 Korean patients over 10 years who developed systemic contact dermatitis after taking Rhus lacquer for indigestion and gastritis (45%), as a health food (39%), in cooked meat, in herbal medicine or by inhalation. Eruptions were maculopapular (65%), erythema multiforme (32%), erythroderma (19%), with pustules, purpura, weals and blisters; all had pruritus, 32% had gastrointestinal symptoms, 26% fever, 70% leucocytosis with neutrophilia (88% of those), and some showed toxic effects on liver and kidney. Only 32% had a known lacquer allergy, and time to onset did not differ between those with and without an allergy history; 59% reacted within a day. All responded to systemic steroids and antihistamines. The authors concluded that Rhus lacquer should not be ingested.

Analysis of 42 patients (24 male, 18 female, mean age 44) with systemic contact dermatitis after ingesting Rhus. Presentations were generalised maculopapular eruption (50%), erythroderma (29%), vesiculobullous lesions (14%) and erythema multiforme-like lesions (7%); 57% had leucocytosis, 74% of those with neutrophilia, and 5% had abnormal liver function. Only 33% had a known lacquer allergy. Peripheral lymphocyte subsets were normal in all 12 patients tested and did not differ by allergy history, leading the authors to argue that part of the eruption reflects a toxic rather than a purely immunological reaction to Rhus.

Record review of 21 Korean patients with systemic contact dermatitis after Rhus ingestion. Season of the year was the most significant epidemiological factor; 66.7% had leucocytosis and 23.8% had raised liver enzymes. The authors note that contact with lacquer-polished tableware is a common route of the initial sensitisation, and call for public education about the risk of eating Rhus.

A further regional Korean case series describing the clinical presentation of systemic contact dermatitis following lacquer ingestion, corroborating the pattern of generalised eruption with systemic features reported in the larger national series.

Eight students learning lacquerware were patch-tested to urushiol before and after lacquer contact, alongside two sensitised controls with no lacquer contact. The paper states that raw lacquer is 60-65% urushiol and its oligomer. Five of the eight became patch-test positive within one month of first contact, and their reactions and dermatitis waned after 9-10 months of continued exposure, indicating occupational hyposensitisation. One subject who had been sensitised before starting reacted strongly throughout. This is the core occupational-sensitisation evidence for the drug: the sensitising dose is small and the sensitisation is fast.

Case report of airborne and systemic pustular dermatitis caused by urushiol from Japanese lacquer, showing that exposure need not be by direct skin contact or ingestion for a severe pustular reaction to occur.

Randomised, double-blind, placebo-controlled trial in 79 Korean adults. The test group (n = 39) took a fermented Rhus verniciflua aqueous extract supplying fustin 129 mg and fisetin 59 mg daily for 12 weeks; controls (n = 40) took lactose placebo. No significant between-group difference was found in liver-disease-related parameters or serum lipid profiles. Note the preparation: this is a fermented bark extract, not the dried lacquer resin Gan Qi, and the trial neither supports nor refutes the safety of the lacquer drug.

Single-centre analysis of 42 patients with advanced or metastatic pancreatic adenocarcinoma treated with a standardised allergen-removed Rhus verniciflua Stokes (aRVS) bark extract between 2006 and 2010. Median overall survival was 7.87 months (95% CI 5.14-10.59) with a 1-year survival rate of 26.2%, which the authors described as compatible with external controls; adverse reactions were mostly mild and self-limiting. The species is the same as Gan Qi but the drug is not: this is a bark extract from which the urushiol allergen has been removed, and the trial says nothing about ingesting lacquer resin.

Retrospective review of 33 patients with advanced non-small-cell lung cancer given allergen-removed Rhus verniciflua bark extract as maintenance after first-line chemotherapy. Median progression-free survival was 5.2 months, disease control rate 93.9%, median overall survival 34.8 months, with no observed haematological toxicity, nephrotoxicity or hepatotoxicity. Uncontrolled and retrospective; again an allergen-removed bark extract, not Gan Qi.

Urushiol-free fermented Rhus verniciflua stem-bark extract was given to Sprague-Dawley rats as single oral doses up to 10,000 mg/kg and for 90 days at up to 5000 mg/kg/day. No deaths and no treatment-related adverse effects were seen on any endpoint; the approximate lethal dose was above 10,000 mg/kg and the no-observed-adverse-effect level above 5000 mg/kg/day, with no target organ identified. The safety demonstrated here belongs to the urushiol-free bark extract and must not be read across to Gan Qi.

OECD-guideline genotoxicity battery on a water extract of bark-removed Rhus verniciflua. The extract partially induced reverse mutation in four bacterial tester strains in the Ames test, but produced no chromosomal aberrations in CHO-K1 cells and no DNA damage in the comet assay in Chang liver cells or C2C12 myoblasts. The authors concluded the bark-removed extract is non-genotoxic; the bacterial signal is worth noting.