Updated July 2026 · 10 min read

Vesicant (Blister) Agents: The ICU Nurse's Deep Dive

Part of the ICU Emergencies Hub — browse every related guide in one place.

Vesicants are the chemical-weapon class that burns skin, eyes, and airways from the inside out. The one that catches teams off guard is sulfur mustard, because the patient can walk in looking almost normal — the injury it caused hours ago hasn't surfaced yet. This is a disease of delay, decontamination, and patient supportive care.

The mechanism: cellular sabotage, not a burn from heat

Sulfur mustard is an alkylating agent — chemically related to the nitrogen-mustard chemotherapies — that cross-links and damages DNA and other cell components. Cells that were exposed are effectively sentenced to die, but the visible damage (blistering, sloughing) takes hours to appear because the death program plays out over time. That delay is the whole clinical signature: little pain and few signs on arrival, then progressive skin, eye, and airway injury unfolding over 2 to 24 hours. Lewisite works faster and differently — an arsenic-based agent that produces immediate burning pain and blistering.

Where it hurts: skin, eyes, airway, and marrow

Skin: erythema first, then large, fragile blisters, typically in warm moist areas (axillae, groin, neck). The blisters are managed like partial-thickness burns — but unlike thermal burns, the fluid inside is not itself a source of active agent once decontamination is complete. Pain control, meticulous wound care, and infection prevention drive the course, and large body-surface involvement is managed with burn-style attention to fluids and sepsis risk (see the Parkland burn resuscitation guide for the fluid framework, while noting vesicant burns generally leak less than thermal burns of the same size).

Eyes: the eyes are exquisitely sensitive — from painful conjunctivitis and photophobia up to corneal damage and, rarely, blindness. Early, copious eye irrigation and ophthalmology involvement matter. Airway: inhaled vesicant sloughs the respiratory mucosa over hours to days, producing pseudomembranes and casts that plug the airway, hoarseness, and an ARDS-like picture — the same relentless pulmonary-toilet problem seen in smoke inhalation injury, managed with humidification, suctioning, bronchoscopy for casts, and lung-protective ventilation.

Bone marrow: in significant exposures, mustard behaves like radiation — it knocks down white cells, then platelets and red cells days later, producing the neutropenic, bleeding-prone patient. Serial counts predict trouble; neutropenic and bleeding precautions apply, mirroring the hematopoietic subsyndrome of acute radiation syndrome.

Treatment: decontaminate, then support

Because mustard has no antidote, decontamination is the only intervention that changes the amount of injury — every minute agent stays on skin is more cells destroyed. Remove all clothing and decontaminate the skin and eyes as fast as safely possible, in the correct zone with proper protective equipment, before the agent can be absorbed further. After that, care is supportive and burn-like: analgesia (blister pain is significant), sterile wound management, fluid and electrolyte support, aggressive pulmonary toilet and ventilation for airway injury, eye irrigation and lubrication, and infection surveillance in a patient who may become both burned and neutropenic.

What the ICU course looks like

Vesicant patients occupy the ICU for the reasons burn patients do: airway injury needing prolonged ventilation and bronchoscopy, large painful wounds at risk of infection, and — with heavy mustard exposure — a marrow that fails over the following week, layering neutropenic sepsis and bleeding risk on top of the burns. It is a long, supportive course. Expect wound care, ventilator management, transfusion and growth-factor support for the marrow, and vigilant infection control.

Why CRNA students should know it cold

On the CRNA path, the vesicant airway is the difficult, deteriorating airway in slow motion — mucosa that sloughs and plugs over hours, demanding early control and ongoing bronchoscopic clearance. The discipline of acting on suspicion and trajectory rather than the current calm exam is exactly the anesthesia mindset.

Bottom line

Blister agents destroy skin, eyes, airway, and — for mustard — bone marrow, often after a deceptive painless delay. Sulfur mustard has no antidote, so decontamination speed determines injury severity, and care is burn-and-ARDS supportive with attention to the failing marrow. Lewisite hurts immediately and has an antidote in dimercaprol (BAL). Decontaminate first, protect yourself, then support the patient through a long course.

This article is general educational information for licensed clinicians and students, not medical advice or a substitute for your institution's protocols, burn-center/poison-center guidance, or a provider's orders. In any suspected exposure, contact Poison Control at 1-800-222-1222 and activate your facility's hazmat/mass-casualty plan. Always follow facility policy and verify every dose independently.