Lidocaine is a widely available local anesthetic used to temporarily relieve pain and itching in the skin. It is commonly found in over-the-counter creams, gels, and sprays intended for minor skin irritations, including sunburns and superficial heat burns. While effective for minor injuries, its use on any burn requires a careful understanding of the specific injury and strict adherence to safety guidelines. Lidocaine should only be considered for first-degree burns and very mild, intact second-degree burns, as improper use on more severe injuries carries significant health risks.
The Role of Lidocaine in Topical Pain Relief
Lidocaine functions as an amide-type local anesthetic by stabilizing the neuronal membrane within the treated area. It works by inhibiting ionic fluxes, specifically blocking voltage-gated sodium channels necessary for the initiation and conduction of pain impulses. By preventing sodium ions from entering the nerve cell, lidocaine temporarily halts the nerve’s ability to send pain signals to the brain, resulting in localized numbness.
This mechanism makes it effective for the superficial pain associated with first-degree burns, which only affect the outer layer of skin (the epidermis). It is also applied to minor second-degree burns where the skin remains largely intact and the pain is localized. However, efficacy is limited to the surface level, and application must be carefully managed to prevent complications.
Pain relief begins quickly, often within minutes of application, and can last for up to a few hours. This temporary numbing effect helps manage the acute discomfort of minor thermal injuries. Its role is strictly to provide symptomatic relief and does not contribute to the healing or repair of the damaged tissue.
Application Guidelines and Safety Warnings
Before applying topical lidocaine, the first step for any burn injury is immediate cooling with cool or lukewarm running water for 10 to 30 minutes. This action stops the burning process and reduces tissue damage. Once the area is cool, lidocaine can be applied sparingly to the minor burn.
Check the product label for concentration, as over-the-counter topical lidocaine is typically limited to a maximum of 4%. Higher concentrations, such as 5% ointments, are often prescription-only and carry a higher risk of systemic absorption. Apply the medication in a thin layer over the affected area, usually no more than three to four times daily, as directed.
A primary safety concern is the risk of systemic absorption, where the medication enters the bloodstream at unsafe levels. This risk increases significantly if the product is applied to large areas, used for prolonged periods, or applied to broken skin (such as open blisters or deep wounds). Applying an occlusive dressing, like plastic wrap, over the treated area can dramatically increase absorption and is strongly discouraged.
Systemic toxicity can lead to serious adverse effects, including central nervous system symptoms (dizziness and seizures) and cardiovascular issues (such as irregular heartbeat). Individuals may also experience a localized allergic reaction, appearing as increased redness, burning, stinging, or irritation that worsens after application. If these signs appear, discontinue use immediately.
When to Seek Medical Attention for Burns
Lidocaine should never be used as a substitute for professional medical care and is inappropriate for any burn beyond a minor first-degree injury. Seek immediate medical attention for all third-degree burns, which often appear charred, white, or leathery, indicating damage to all layers of the skin and sometimes underlying tissue. These severe injuries may even be painless due to nerve damage.
Professional evaluation is necessary for second-degree burns larger than two to three inches in diameter or the size of the injured person’s palm. Any burn occurring on sensitive or high-risk areas requires professional assessment, regardless of size. These locations include the face, hands, feet, major joints, or genitals, as burns here can lead to functional impairment or permanent disfigurement.
Burns caused by chemical exposure or electricity must be evaluated by a healthcare provider due to the potential for unseen internal damage. Medical attention is mandatory if the burn shows signs of developing an infection, such as persistent fever, foul odor, increased swelling, spreading redness, or pus. If pain is not controlled by over-the-counter oral pain relievers, this indicates a more serious injury requiring intervention.