An acid burn occurs when a corrosive substance with a low pH comes into contact with the skin, initiating a chemical reaction that causes tissue damage. Acids achieve this by coagulating and denaturing proteins in the skin cells, killing them and causing a lesion. The severity of the injury depends on the acid’s concentration, the volume of the spill, and the duration of contact with the body. Since chemical activity continues as long as the substance remains on the skin, immediate action is required to stop the destructive process.
The Critical First Step
The most effective method for halting the corrosive action of an acid on the skin is physical dilution and removal using copious amounts of running water. This method immediately flushes the chemical away from the tissue surface, significantly reducing the concentration of the acid and slowing the chemical reaction. The goal is not to neutralize the acid chemically, but to dilute it to a non-damaging concentration and physically wash it away from the wound site.
Action must be taken immediately; place the affected area under a gentle stream of cool, running water. Continuous flushing should be maintained for a minimum of 20 minutes, or longer, to ensure the acid is thoroughly removed. If the chemical is in a powdered form, it should be lightly brushed away before water is applied, as water can sometimes react with dry chemicals to create a more damaging solution.
Simultaneously, remove any contaminated clothing or jewelry. Fabric can absorb and hold the acid against the skin, continuing the chemical burn despite water irrigation. Water flow and the removal of saturated materials stop the corrosive process and prevent the burn from progressing to deeper tissue layers.
Understanding Chemical Neutralization
In chemistry, neutralization is defined as the reaction between an acid and a base (alkali) to produce a salt and water, which are generally less harmful substances. The literal answer to what neutralizes an acid is a base.
Common household weak bases include baking soda (sodium bicarbonate) and certain antacid tablets. These substances could theoretically be applied to an acid to bring the pH closer to a neutral value of 7. The intent of using a weak base is to counteract the corrosive hydrogen ions (H+) of the acid with the hydroxide ions (OH-) of the base.
While this chemical definition of neutralization is accurate, attempting this reaction on human skin is widely discouraged in first aid practice. Although the concept is chemically sound, the process introduces a significant complication when the reaction occurs directly on living tissue, which is why water dilution is the universally recommended first response.
Why Chemical Neutralization on Skin is Dangerous
The primary reason against chemically neutralizing an acid burn is the exothermic nature of the acid-base reaction, meaning it releases heat into the surrounding environment. When an acid and a base combine, the rapid formation of salt and water generates thermal energy.
Applying a neutralizing agent, such as baking soda, directly to an acid burn creates a concentrated, rapid chemical reaction right on the skin’s surface. The sudden release of heat from this reaction can cause a secondary thermal burn, compounding the initial chemical injury. This dual damage—chemical and thermal—can significantly increase the overall severity and depth of the wound.
The generated heat can also drive the corrosive acid deeper into the tissue, causing more extensive damage. The reaction is difficult to control, and using an incorrect amount of the neutralizing agent can leave residual base on the skin, which then poses its own chemical burn risk. For these reasons, the controlled, gentle action of water dilution is favored over the unpredictable, heat-releasing nature of chemical neutralization.
Post-Exposure Care and Medical Intervention
After flushing is complete, the first aid response transitions to wound care and professional assessment. It is important to seek prompt medical attention for any acid burn, regardless of how minor the injury may initially appear. Chemical damage can continue beneath the surface, and a medical professional must assess the extent of the tissue destruction.
Before transport, the wound should be loosely covered with a clean, dry, non-adherent dressing, such as sterile gauze. This covering helps protect the damaged skin from contamination without sticking to the wound surface. It is important not to apply any creams, ointments, or home remedies to the burn before a medical evaluation.
When seeking medical care, provide healthcare providers with information about the exposure. Specifically, the name and concentration of the acid, the estimated duration of contact, and the steps taken for first aid should be relayed to the medical team. This information guides their treatment decisions, including potential specialized interventions beyond standard burn care.