Abstract： Objective To determine the levels of plasma histamine and oxidative status in patients with dermatographism before and after the treatment with anti-histamine drugs. Methods Totally, 85 patients with dermatographism were randomly divided into two groups to receive oral desloratadine and cetirizine respectively for 4 weeks. Enzyme linked immunosorbent assay (ELISA) was performed to detect the plasma level of histamine, superoxide dismutases (SOD), glutathion peroxidase (GSH-PX) and malondialdehyde (MDA) in all the patients before and after the treatment and in 15 normal human controls. The efficacy of desloratadine and cetirizine for dermatographism was estimated. Results The response rate was 83.72% and 78.57% in patients treated with desloratadine and those with cetirizine, respectively (x2 = 0.369, P> 0.05). The untreated patients with dermatographism showed an elevation in the plasma level of histamine (3.87 ± 1.21 ng/ml vs. 1.76 ± 0.56 ng/ml, P< 0.05) and MDA (3.86 ± 1.03 nmol/ml vs. 2.19 ± 0.82 nmol/ml, P< 0.05), but a decline in the activity of SOD (86.29 ± 19.9 U/ml vs. 112.12 ± 27.88 U/ml, P< 0.05) and GSH-PX (74.52 ± 47.67 vs.915.06 ± 115.96, P< 0.05) compared with the normal human controls. The treatment with antihistamine induced a reduction in the plasma level of histamine (1.61 ± 0.47 ng/ml vs. 3.87 ± 1.21 ng/ml, P< 0.05) and MDA (2.65 ± 0.77 nmol/ml vs. 3.86 ± 1.03 nmol/ml, P< 0.05), but an increment in the activity of GSH-PX (921.46 ± 157.37 vs.74.52 ± 47.67, P < 0.05) with no changes of SOD in patients with dermatographism. Conclusions In patients with dermatographism, plasma histamine is increased and there is an imbalance of oxidation-antioxidation.Desloratadine and cetirizine are effective for the treatment of dermatographism.