Duration of venom immunotherapy still remains questionable since some patients lose their sensitivity. Venom immunotherapy can be stopped when venom skin tests and specific IgE are negative. Five studies have been performed to prospectively study the evolution of skin tests and specific IgE after three to six years of maintenance immunotherapy. Four studies showed that skin tests became negative in 30 to 55% of patients depending upon the venom species and the duration of the treatment. Mean specific IgE declined in most studies but were negative only in a substantial number of patients in the European studies. Adults and children had a similar rate of disappearance of skin test reactivity. In one study, skin tests were negative in 1/3 of patients after one year of treatment suggesting that venom immunotherapy may be given for a short period of time in some patients.