Cantharidin is a chemical weapon that is naturally produced by blister beetles. Topical cantharidin is used for dermatological purposes of removing warts and molluscum. Molluscum is the result of a virus that can cause a skin disease, resulting in bumps on the skin. Cantharidin is applied to the wart or molluscum in order to peel away the layers of wart or bump growth, without causing any residual scarring as a result of the treatment.
Cantharidin is used as an effective treatment in wart and molluscum removal. When cantharidin is applied to a growth, blisters form within one to two days. After application, removal of the growth is gone, and healing is completed within a week. Cantharidin is usually left on a growth for a few hours, and a nonporous tape may be applied in order to increase absorption of the cantharidin.
The use of cantharidin should only be applied by a physician due to the effects of blistering. In an abstract from the Archives of Dermatology, people who have fair skin should adjust contact time with cantharidin because they tend to blister easily. If cantharidin is improperly used, severe blistering can occur. Ingestion of cantharidin can prove to be fatal, and cantharidin should never be used around the eyes or eyelids, as it can cause erosion of membranes around the eyes.
After the use of cantharidin, the chemical can cause sensations of tingling, itching and burning. These symptoms may occur within a few hours of application. Burning is most noticeable once the blisters begin to form on the application site. The skin can also become swollen and feel uncomfortable to the touch. The skin can be very sore for up to a week, but once the area as completely healed, the wart or growth is gone, with no visible scarring.
Never pop the blister once it has formed. Popping a blister can lead to an infection of the skin. You can use ointment such as Bacitracin and keep the blister covered, which will help in healing. Ice packs can be used on the localized site in order to reduce swelling and help soothe the pain that may be associated with cantharidin treatment. Very rarely can infection occur, but if you notice you are running a fever above 101 degrees F, if you have pus oozing from the site or if you have extreme redness and swelling at the treated site, call your doctor immediately.
Sometimes intense burning and itching can occur. In the abstract from the Archives of Dermatology, what is known as satellite warts may also occur. These warts may form a small ring around the original site of the wart that was removed. Pigmentation of the skin may also occur, but this is rare.