Bums, chemical skin exposure

In a study of 27 cases of acid and alkaline chemical injuries from India, Sawheny and Kausish [31] noted that such injuries differed from thermal bum injuries [31]. There were a total of 562 patients admitted to a bum center over a 5-year time period, and of these 16 were acid chemical injuries (nitric and sulfuric acids), while 11 were sodium hydroxide exposures. At 3 weeks after chemical skin exposure, wound infections developed in 2/3 of patients and all chemical skin injury bums were infected by 4 weeks after exposure. While copious potable water washing was done, it was often quite delayed and seemed to be of limited efficacy [31]. 

Strong acids and strong alkaUes can severely bum the skin, chromium compounds can produce skin rashes, and repeated exposure to solvents causes removal of natural oils from the skin. Infection is always a concern for damaged skin. Absorption through the skin is possible for materials that are appreciably soluble iu both water and oil, eg, nitrobenzene, aniline, and tetraethyllead. Other materials can be absorbed if first dissolved iu extremely good solvents, eg, dimethyl sulfoxide. Subcutaneous iujection can occur accidentally by direct exposure of the circulatory system to a chemical by means of a cut or scratch or iuadvertent penetration of the skin with a hypodermic needle. 

Hardee, H. C., and D. O. Lee. 1978. A simple conduction model for skin bums resulting firom exposure to chemical fireballs. Fire Res. 1 199-205. 

Irritant dermatitis does not involve an immune response and is typically caused by contact with corrosive substances that exhibit extremes of pH, oxidizing capability, dehydrating action, or tendency to dissolve skin lipids. In extreme cases of exposure, skin cells are destroyed and a permanent scar results. This condition is known as a chemical burn. Exposure to concentrated sulfuric acid, which exhibits extreme acidity, or to concentrated nitric acid, which denatures skin protein, can cause bad chemical bums. The strong oxidant action of 30% hydrogen peroxide likewise causes a chemical bum. Other chemicals causing chemical bums include ammonia, quicklime (CaO), chlorine, ethylene oxide, hydrogen halides, methyl bromide, nitrogen oxides, elemental white phosporous, phenol, alkali metal hydroxides (NaOH, KOH), and toluene diisocyanate. 

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