52 patients with a clinical diagnosis of
verruca plantaris were entered into a randomised study of
acyclovir cream versus placebo cream versus liquid
nitrogen. 47 completed the initial 8-week assessment period. At first, liquid
nitrogen was used as a positive control but after the entry of 33 patients it was discontinued as an initial
therapy in order to obtain maximal numbers of patients on the cream treatments. At the end of the 8-week assessment period 5 of 18 (placebo cream), 7 of 18 (
acyclovir cream) and 1 of 11 (liquid
nitrogen) patients were completely cleared of their plantar
warts. Patients who failed to clear on cream or liquid
nitrogen treatments after the initial assessment period but who wished to continue
therapy were subsequently treated with liquid
nitrogen. Of a total of 27 patients treated vigorously with liquid
nitrogen, for periods of time ranging from 2 to 34 weeks, only 11 were completely cleared of their
warts at the end of the study. It is concluded that liquid
nitrogen should not be considered as a routine treatment for plantar
warts and that
acyclovir cream is no better than placebo in the treatment of this condition.