Clinical features of 31 patients with systemic contact dermatitis due to the ingestion of Rhus (lacquer)

In Korea, Rhus has been used as a folk medicine to cure gastrointestinal di seases and as a health food, We review the clinicopathological and laborato ry findings in patients with systemic contact dermatitis caused by intake o f Rhus. We reviewed medical records and histopathological sections from 31 patients during a 10-year period. The male/female ratio was 1.4 : 1 and the average age was 43.8 years (range 22-70). Ten patients (32%) had a known h istory of allergy to lacquer. Rhus was ingested to treat gastrointestinal p roblems including indigestion and gastritis (45%), and as a health food (39 %), in cooked meat, in herbal medicine, or taken by inhalation. The patient s developed skin lesions such as a maculopapular eruption (65%), erythema m ultiforme (EM, 32%), erythroderma (19%), pustules, purpura, weals and blist ers. Erythroderma was very frequent in patients with a known history of all ergy to lacquer, but maculopapular and EM-type eruptions were more frequent ly observed in those without a history of allergy All patients experienced generalized or localized pruritus. Other symptoms included gastrointestinal problems (32%), fever (26%), chills and headache; many developed leucocyto sis (70%) with neutrophilia (88%), while some showed toxic effects on liver and kidney. Fifty-nine per cent of patients observed cutaneous or general symptoms within a day after ingestion of Rhus. There was no difference in t he time lag for symptoms to develop between patients allergic and not aller gic to Rhus. All patients responded well to treatment with systemic steroid s and antihistamines. Common histopathological findings were vascular dilat ation, perivascular lymphohistiocytic infiltration, and extravasation of re d blood cells in the upper dermis. Rhus lacquer should not be ingested in v iew of its highly allergic and toxic effects.