injuries poisoning
Vesicant Chemical Warfare Agents
Symptoms and Signs of Vesicant Chemical Injuries
Mustard compounds cause intense and increasing skin pain, erythema, and blister formation after a latent period. The latent period is inversely correlated with dose but is usually at least a few hours (and up to 36 hours). Blisters caused by sulfur mustard sometimes resemble a string of pearls around a central area that appears unaffected but is actually too damaged to blister; blisters caused by nitrogen mustard are less likely to show this pattern. Blisters may become large and pendulous. Painful chemical conjunctivitis causing reflex lid closure occurs earlier than skin symptoms but still after a delay often of hours. The cornea may become cloudy. Respiratory manifestations include cough, laryngospasm, hoarseness, wheezing, and inspiratory stridor; these also are the typical signs and symptoms of exposure to type 1 pulmonary agents and, like skin injuries, occur after a latent period that is inversely correlated with dose but is usually at least a few hours. Chest tightness and dyspnea may occur with severe exposure. Nausea may occur after moderate to high doses. Lewisite causes pain within a minute or so of skin exposure. Erythema is often noticeable in 15 to 30 minutes, and blisters develop after several hours. The blisters usually form at the center of the erythematous area and spread peripherally. Pain is usually not so severe as that caused by mustard and begins to subside after blisters form. Irritation of mucosal membranes and large airways occurs soon after inhalation and leads to coughing, sneezing, and wheezing. After a few hours, type 2 symptoms (chest tightness and shortness of breath) occur. Skin contact with phosgene oxime causes intense, "nettling" pain and blanching within 5 to 20 seconds. The affected skin then turns gray with an erythematous border. Between 5 and 30 minutes after exposure, edema leads to wheal formation (urticaria). During the next 7 days, the skin becomes dark brown and then black as necrosis of skin and underlying subcutis and muscle occurs. If not surgically excised, the lesion may persist for more than 6 months. In the respiratory tract, phosgene oxime causes pulmonary edema even at low doses. 