A chemical burn is tissue damage caused by contact with a corrosive substance, such as a strong acid, alkali, oxidizer, or solvent. These injuries range from minor irritation to severe destruction of skin, eyes, and internal organs. Recognizing these visual cues is important because the severity is often not immediately obvious, and rapid action is necessary to halt the chemical reaction and minimize tissue damage.
How Different Chemicals Damage Tissue
Acids and alkalis, the two main categories of corrosive agents, create visually distinct types of tissue death. Acids typically cause coagulation necrosis by denaturing the proteins in the skin. This immediate protein change forms a thick, dry, and often dark scab called an eschar, which acts as a barrier to limit the acid’s penetration into deeper tissue layers.
The appearance of acid burns is often leathery and can be brown, gray, or black, though some acids may leave the tissue white or clear. Alkalis, or strong bases, cause liquefaction necrosis and saponification of fats. This process dissolves the cell membranes and liquefies the tissue, allowing the chemical to penetrate deeply into underlying layers.
Alkali burns may initially appear less severe, often presenting as a slippery, whitish, or gray area that continues to destroy tissue well after initial contact. This lack of a protective eschar means the damage can be extensive and may involve muscle, tendon, and bone. Hydrofluoric acid is an exception, which, despite being an acid, causes liquefaction necrosis and deep tissue destruction similar to an alkali burn.
Visual Identification Based on Burn Severity
Superficial burns, often called first-degree burns, affect only the outermost layer of skin, the epidermis. These burns appear as simple redness, or erythema, and are painful but do not produce blisters. The skin may be dry and warm to the touch, and it will blanch, or turn white, when light pressure is applied.
Partial thickness burns, or second-degree burns, extend through the entire epidermis and into the underlying dermis layer. The defining visual characteristic is the formation of fluid-filled blisters. The skin underneath the blisters will be intensely red or mottled, may appear wet or weeping, and the area will be highly sensitive and painful.
Deep partial-thickness burns may look drier, be yellowish-white, and blanch slowly when touched. Full thickness burns, known as third-degree burns, destroy both the epidermis and the entire depth of the dermis. The appearance is often white, waxy, leather-like, or charred, and the skin may look sunken.
These burns destroy nerve endings, meaning the affected area itself will be numb or painless, though the surrounding, less-severe areas may still hurt. Burns that involve deeper structures like muscle, tendon, or bone are sometimes referred to as fourth-degree burns and have a distinctly charred appearance. The final appearance of the burn’s severity may take several days to fully develop, particularly with alkali exposures.
Immediate First Aid and Emergency Action
The first step in responding to a chemical burn is to ensure the safety of the responder by putting on protective gloves and minimizing personal exposure. Any contaminated clothing or jewelry should be rapidly removed while the flushing process is underway, unless the material is stuck to the skin. If the chemical is a dry powder, such as lime, it is important to brush off the excess material before water is applied, as water can sometimes activate or intensify the chemical reaction.
Continuous flushing of the affected area with large amounts of cool running water is the immediate treatment. Flushing should continue for at least 20 minutes to dilute and wash away the chemical. Do not use a hard spray of water, which could damage the burned tissue, and avoid extreme temperatures like ice water, which can worsen the injury.
Do not attempt to neutralize the chemical with an acid or alkali substance, as this can cause a heat-generating reaction that deepens the burn. If a burning sensation persists after the initial 20 minutes of flushing, continue rinsing for an additional 10 to 15 minutes. Seek professional medical help immediately by calling 911 or Poison Control for any full-thickness burn signs, large area burns, or any chemical exposure to the eyes or face.
Once flushing is complete, a small burn can be loosely covered with a clean, dry, sterile dressing. Do not apply any ointments, creams, or home remedies, as these can trap the chemical or interfere with medical assessment. Special chemicals like carbolic acid or elemental metals require specific protocols, so consulting Poison Control is important if the specific agent is known.