Squaric Acid Dibutylester Superior Treatment for Cutaneous Warts

Plane (flat) warts on the fingers
Plane (flat) warts on the fingers
The treatment successfully reduced the number and size of warts that had previously not responded to therapy.

Squaric acid dibutylester (SADBE) is significantly more effective than vehicle for the  treatment of recurrent cutaneous warts, according to results published in Dermatitis.

In order to evaluate the effectiveness of SADBE on cuteneous warts, researchers conducted a randomized double-blind vehicle-controlled clinical trial. They randomly assigned 36 patients to receive SADBE (18 cases) or vehicle (18 cases) for 8 weeks, after which they clinically evaluated participants for wart number/size reduction rate and Investigator Global Assessment. Patients who were responsive continued treatment for up to 40 weeks, and patients who were not responsive were either switched to SADBE for up to 48 weeks (if in the vehicle group) or withdrawn from the study (if taking SADBE).

Patients in the SADBE group showed a significant reduction in wart number (P =.020) and size (P =.010) at 8 weeks, with clearing rates of 41.2% compared with 12.5% in the vehicle group.

The investigators noted that the mechanism of action of SADBE is still unclear, suggesting that the “sensitizing agent could act by inducing a type IV hypersensitive response in an HPV-infected tissue,” or possibly a nonspecific anti-inflammatory reaction, they wrote. “However, the possibility of systemic immunostimulation cannot be excluded because regression of warts on an untreated area is often observed.”

“Our study indicates that SADBE efficacy is statistically superior to vehicle in patients with multiple lesions who had previously undergone conventional therapies with unsatisfactory outcomes,” the investigators concluded. 

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Dall’Oglio F, Luca M, Barresi S, Micali G. Treatment of multiple-resistant and/or recurrent cutaneous warts with squaric acid dibutylester: a randomized, double-blind, vehicle-controlled clinical trial. Dermatitis. 2017;28(5):308-312.