Abstract: 【Abstract】 Objective To analyze clinical characteristics of cutaneous delayed-type hypersensitivity caused by injection of equine tetanus antitoxin （TAT） or equine anti-tetanus immunoglobulin F（ab′）2 . Methods Clinical data were collected from 181 outpatients or inpatients with cutaneous delayed-type hypersensitivity caused by injection of equine TAT or anti-tetanus immunoglobulin from 2008 to 2020, and retrospectively analyzed. Results Before the injection of equine TAT or anti-tetanus immunoglobulin, skin test was negative in 171 （94.47%） of the 181 patients, and the 10 （5.53%） patients with positive skin test responses received desensitization injection. Among the 181 patients, there were 118 males and 63 females aged from 11 to 68 years, with the disease duration of 1 to 7 days and alatency period of 4 to 14 days. There was no significant difference in the clinical manifestations between the patients receiving injection of TAT （130 cases） and those receiving injection of equine anti-tetanus immunoglobulin （51 cases）. Urticaria-like rashes were the main clinical manifestation, and infiltrative erythema occurred at the injection site in 12 patients, of whom 10 developed generalized urticaria all over the body. Of the 181 patients, 163 （90.06%） presented with generalized skin rashes, and 56 （30.94%） had systemic symptoms such as chest tightness, fever, etc, of whom 15 （26.79%） had a history of allergies and 6 with severe symptoms had no history of allergies. Thirty-four （18.78%） patients had single or multiple laboratory abnormalities, such as increased white blood cell counts, elevated C-reactive protein level and urinary glucose, and presence of occult blood in urine. All cases responded well to the treatment with antihistamines and glucocorticoids. The treatment duration ranged from 3 to 10 days, and the outcome was good. Conclusion TAT- or anti-tetanus immunoglobulin-induced cutaneous delayed-type hypersensitivity may still occur in patients with a negative skin test or after desensitization treatment, and mainly manifests as urticaria-like rashes.

Key words: Tetanus antitoxin, Immunoglobulins, Hypersensitivity, Hypersensitivity, delayed, Drug eruptions, Equine tetanus antitoxin, Equine antitetanus immunoglobulin F（ab′）2