squaric acid (SADBE)

Squaric Acid Dibutylester

squaric acid

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This medication requires a prescription from your doctor.

0.2% solution with 2% one-time sensitizing solution

Squaric acid dibutylester (sometimes called just squaric acid or SADBE) is used as an immunotherapy for warts. It is often a preferred treatment for pediatric patients because it is non-toxic and has few side effects. In one study conducted on 188 pediatric patients, 84% of the patients who were treated with squaric acid showed complete resolution of their warts after a 3-month treatment course. In addition to warts, this therapy has been used to treat patients with alopecia areata, which is a loss of hair caused by an immune dysfunction. Research is also currently being conducted on squaric acid’s use for treating cold sores.

Squaric Acid for Warts

Warts are an infection of the skin caused by human papillomaviruses (HPV) and are especially common in children. Compared to treatments like cryotherapy and lasers, squaric acid immunotherapy causes less damage to surrounding skin. The side effects generally are only a rash similar to a mild allergic reaction. Compared to cryotherapy, squaric acid treatment is relatively painless and much more tolerable. This therapy may be especially useful for warts affecting areas like the face and neck to avoid the tissue destruction associated with more destructive treatments.

Squaric acid works by causing an inflammatory reaction in the skin similar to a mild allergic reaction. Lymphocytes migrate to the area of the skin where the solution has been applied after the body has already been sensitized. The warts are then destroyed in the allergic inflammatory process. Squaric acid works well for this process because it will almost never be encountered in daily life unless it is purposefully applied to the skin, and when it is applied the allergic reaction is mild.

Administering Squaric Acid

First, a 2% solution is applied to a small, dime-sized area on the arm for sensitization. The 2% solution is not applied to the warts, but to arm to sensitize the body to the squaric acid. It may take up to two weeks for a skin reaction to occur where the sensitizing solution is applied. The skin reaction will involve redness developing around the application sight.

After the sensitization is complete, a 0.2% solution is used directly on the warts. The 0.2% solution is applied regularly several times per week, for a 2-3 month treatment course. Treatment courses can be repeated if they are not effective the first time.

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  • Examining the efficacy and safety of squaric acid therapy for treatment of recalcitrant warts in children. – Pediatric Dermatology (PubMed)
  • Usefulness of topical immunotherapy with squaric acid dibutylester for refractory common warts on the face and neck – Japanese Dermatological Association (Wiley Online Library)
  • Immunotherapy for Recalcitrant Warts in Children Using Intralesional Mumps or Candida Antigens – Pediatric Dermatology (Wiley Online Library)

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