Abstract
Vesicants (sulfur mustards, lewisite, and nitrogen mustards) are chemicals that cause blistering of the skin. Developed as chemical warfare agents, their biological activity is complex and not fully understood. These vesicants in liquid or vapor form are capable of causing injury to most any tissue. Contact with the skin results in erythema and blistering. Exposure to vapors produces ocular and respiratory effects which occur at exposures below those causing dermal effects. Systemic and long-lasting effects may occur, especially following acute exposures that result in severe injury. Multi-organ involvement and fluid loss shock resulting in death may follow severe exposures. As alkylating agents, all of the mustards are known or potential carcinogens. The carcinogenic potential of lewisite in humans is equivocal.
Toxicity data in animals are available for the vesicants although data on sulfur mustard and lewisite are more extensive than for the nitrogen mustards. Data from tests with human volunteers and occupational exposure information are also available. These data collectively have provided a basis for the development of exposure standards, guidelines, and criteria for use in emergency planning and emergency response, and remediation efforts.
The mode of action of the vesicants is complex, not fully understood, and represents an ongoing area of investigation especially with respect to treatment of vesicant-induced injury. Prevention of exposure and decontamination are critical initial steps in eliminating or minimizing injury. With the exception of arsenic chelating antidotes (e.g., British anti-lewisite; BAL) for lewisite, no antidotes exist for the vesicant agents. Medical management currently focuses on palliative treatment of signs and symptoms.