What happens once alcohol is in the skin?

Entering the skin is not the same as entering the bloodstream

The stratum corneum, the outermost skin layer, controls how readily chemicals pass into deeper skin. The outer skin layer acts as a barrier, not an open invitation to everything in the bottle. A chemical entering this layer has not necessarily reached the circulating blood. Dermal absorption means a chemical passes through the skin and into the body.4

The amount absorbed depends on whether skin is intact or damaged, the area exposed, the concentration and the duration of contact. Skin thickness, water content and temperature also matter. A brief application to intact hands and prolonged contact over damaged skin are therefore different exposures, even when both involve ethanol.4

What happens to alcohol applied to skin?

Hand sanitiser ethanol evaporates during normal use, limiting the time available for absorption. Repeated use can produce low, measurable blood alcohol concentrations, but those measurements do not automatically mean the alcohol entered through skin. Breathing the vapour is another route. Experiments separating the two routes found negligible skin absorption, while inhaling concentrated vapour produced temporary breath alcohol readings.12

Ethanol also acts as a penetration enhancer: it can help other chemicals in a formulation pass through skin. Local effects and whole body effects are separate concerns. Ethanol exposure can cause irritation or contact dermatitis, meaning inflammation after contact with a substance, even when very little alcohol reaches the blood. Children, particularly those exposed through cut or damaged skin, need extra caution because toxicity through skin has occurred in that setting.14

What if the alcohol came from drinking?

After drinking, ethanol in the blood can diffuse through the epidermis, the skin's outer section, and the stratum corneum before reaching the air above the skin. Wearable alcohol sensors use this outward movement to estimate blood alcohol concentration. This is a different situation from applying an alcohol containing product to the surface.3

Transport models show that alcohol above the skin peaks later, reaches a lower peak and falls more slowly than blood alcohol. During elimination, the stratum corneum can contain a higher ethanol concentration than the blood. The delay depends on the physical properties of the outer skin layer, including its thickness and how readily ethanol dissolves and moves within it. A skin alcohol reading is therefore not interchangeable with a blood alcohol reading at the same moment.3

What should you do if alcohol rubs sting?

Alcohol rubs commonly sting skin that already has irritation or dermatitis; stinging alone is not a sign of allergy. Alcohol rubs are actually less irritating than soap and water. Replacing every application with another wash can therefore add irritation rather than solve it. Follow workplace hand hygiene rules, including when alcohol rub is suitable and when washing is required.5

Apply moisturiser whenever hands feel dry and after every wash. Moisturisers need repeated application because their effects do not last long, which is inconvenient for anyone hoping to finish hand care permanently. Keep moisturising after irritation looks better, because hand skin remains vulnerable for several months. Seek advice from a pharmacist or GP for redness, rashes, blisters, itching, cracking or bleeding.56

If you take disulfiram, a medicine used in alcohol treatment, concentrated sanitiser vapour in confined spaces is a separate concern. Disperse fumes and avoid deliberately inhaling them. A reaction from skin application alone is highly unlikely.2