Incidence of systemic reactions during rush immunotherapy

Rush immunotherapy (RIT) was administered on an outpatient basis to 11 patients. Of these, nine had asthma and four were steroid-dependent. All patients received extracts containing a mixture of antigens to which they were prick-sensitive. FEV1s were greater than 80% predicted before starting RIT. Four patients each required a 1 week steroid "burst" to accomplish this. A series of 8 subcutaneous injections were given starting with 0.3 mL of 1:100,000 (wt/vol) and ending with 0.10 mL of 1:100 (wt/vol) 1.5 days later. A dose of 0.15 mL of 1:100 was given weekly after that. All patients but one completed the RIT. Four had sore arms, four had pruritus and/or sneezing, four developed wheezing, and one experienced anaphylaxis with hypotension. Systemic reactions tended to occur at the higher doses and usually more than 30 minutes after a previous injection. Subsequent weekly injections were tolerated without reactions by seven of the patients. Rush immunotherapy is an effective method for administering a high dose of allergen in a very short time period. Due to the risk of systemic reactions it needs to be given under carefully controlled conditions.