Clinical effects are dose-dependent. At low doses, skin irritation and blistering occurs; at higher doses, systemic toxicity can also be seen. While tissue damage occurs within minutes of exposure, initial signs and symptoms are typically delayed for several hours. Skin findings include erythema that progresses to blister formation over 24 hours. Warm, moist areas such as the axillae and groin are particularly susceptible. Ocular manifestations are similarly delayed and include lid edema, conjunctival injections, and, with severe exposure, corneal ulceration. Respiratory involvement begins with sore throat, cough, and hoarseness, and can in rare instances of overwhelming exposure progress to pulmonary edema. Early tachypnea or dyspnea suggests a poor prognosis.