GLUTARALDEHYDE

Glutaraldehyde 10 per cent cutaneous solution has similar properties to formaldehyde gel. However, it appears to have no advantage over formaldehyde and may be a more potent skin sensitiser.

It stains skin brown, but this fades once treatment is discontinued. As with formaldehyde gel, glutaraldehyde solution is particularly recommended for verrucas and is applied twice daily.

SILVER NITRATE

Silver nitrate is a caustic agent; it is used in the form of a pencil (95 per cent toughened with 5 per cent potassium nitrate) to destroy warts, verrucas and other skin growths. Unlike some other treatments, silver nitrate pencil is used for only a short period; the manufacturer of the only commercially available product recommends daily applications for three days for warts and six days for verrucas.

TRICHLOROACETIC ACID

Trichloroacetic acid is caustic and astringent. It is available as a gel in a pen-type device for the treatment of warts and verrucas. A single drop of gel is applied twice daily for four days and repeated if necessary up to four times, with four-day breaks between treatments.