53 6 Chemical Skin Burns Magnus Bruze, Birgitta Gruvberger, Sigfrid Fregert Contents aged to a point where there is no return to viability; in other words, a necrosis develops [7, 43, 45]. One 6.1 Introduction . 53 single skin exposure to certain chemicals can result 6.2 Definition . 53 in a chemical burn. These chemicals react with intra- 6.3 Diagnosis . 56 and intercellular components in the skin. However, 6.4 Clinical Features . 56 the action of toxic (irritant) chemicals varies caus- 6.5 Treatment . 57 ing partly different irritant reactions morphologically. 6.6 Complications . 58 They can damage the horny layer, cell membranes, 6.7 Prevention . 59 6.8 Summary . 59 lysosomes, mast cells, leukocytes, DNA synthesis, References . 60 blood vessels, enzyme systems, and metabolism. The corrosive action of chemicals depends on their chem- ical properties, concentration, pH, alkalinity, acidity, temperature, lipid/water solubility, interaction with 6.1 Introduction other substances, and duration and type (for exam- ple, occlusion) of skin contact. It also depends on the Chemical skin burns are particularly common in in- body region, previous skin damage, and possibly on dustry, but they also occur in non-work-related en- individual resistance capacity. vironments. Occupationally induced chemical burns Many substances cause chemical burns only when are frequently noticed when visiting and examining they are applied under occlusion from, for example, workers at their work sites. Corrosive chemicals used gloves, boots, shoes, clothes, caps, face masks, ad- in hobbies are an increasing cause of skin burns. Dis- hesive plasters, and rings. Skin folds may be formed infectants and cleansers are examples of household and act occlusively in certain body regions, e.g., un- products which can cause chemical burns. However, der breasts and in the axillae. Many products, which in most cases, the cause of a chemical burn is obvious under ordinary skin exposure conditions cause weak to the affected persons and damage is minimal and irritant reactions or irritant contact dermatitis, can heals without medical care, so medical attention is under occlusion cause chemical burns, e.g., deter- not sought. Sometimes the chemical burns are severe gents, emulsifiers, solvents, plants, woods, topical me- and extensive with the risk of complications and long- dicaments, toiletries, insecticides, pesticides, preser- term disability. In the acute stage, there is a varying vatives, cleansers, polishes, paint, plastic monomers, risk of systemic effects, including a fatal outcome, and Portland cement. Wet cement can usually be depending on exposure conditions and the incrimi- handled without causing a chemical burn, but when nating agent. For these reasons it is important for the present under occluding clothes for some hours, it physician to have knowledge of corrosive chemicals can cause severe skin damage, e.g., on knees. White as well as of chemical burns with regard to their clini- spirit causes only slight dryness at open application, cal manifestations, specific medical treatments, and but causes blisters under occlusion. preventive measures. There are different mechanisms for reactions be- tween skin components and agents causing chemical and thermal burns. Chemical agents cause progres- 6.2 Definition sive damage until either no more chemical remains unreacted in the tissue or the agent is inactivated A caustic burn (chemical burn) is an acute, severe by treatment, while thermal damaging effects cease irritant reaction by which the cells have been dam- shortly after removal of the heat source. 54 Magnus Bruze, Birgitta Gruvberger, Sigfrid Fregert Acids Miscellaneous Acetic acid Acethyl chloride Acrylic acid Acrolein Benzoic acid Acrylonitril Boric acid Alkali ethoxides Bromoacetic acid Alkali methoxides Chloroacetic acids Allyl diiodine Chlorosulfuric acid Aluminium bromide Fluorophosphoric acid Aluminium chloride Fluorosilicic acid Aluminium trichloride Fluorosulfonic acid Ammonium difluoride Formic acid Ammonium persulfate Fumaric acid Ammonium sulfide Hydrobromic acid Antimone trioxide Hydrochloric acid Aromatic hydrocarbons Hydrofluoric acid Arsenic oxides Lactic acid Benzene Nitric acid Benzoyl chloride Perchloric acid Benzoyl chlorodimethylhydantoin Peroxyacetic acid Benzoyl chloroformiate Phosphonic acids Borax Phosphoric acids Boron tribromide Phthalic acids Bromine Picric acid Bromotrifluoride Propionic acid Calcium carbide Salicylic acid Cantharides Sulfonic acids Carbon disulfide Sulfuric acid Carbon tetrachloride Tartaric acid Chlorinated acetophenons (tear gas) Toluenesulfonic acid Chlorinated solvents Chlorobenzene Alkalis o-chlorobenzylidene malononitrile (tear gas) Chlorocresols Amines Chloroform Ammonia Chlorophenols Barium hydroxide Chromates Calcium carbonate Chromium oxichloride Calcium hydroxide Chromium trioxide Calcium oxide Creosote Hydrazine Cresolic compounds Lithium hydroxide Croton aldehyde Potassium hydroxide Dichloroacetyl chloride Sodium carbonate Dichromates Sodium hydroxide Dimethyl acetamide Sodium metasilicate 6 Chemical Skin Burns 55 Miscellaneous Miscellaneous Dimethyl formamide Phosphorus oxides Dimethyl sulfoxide (DMSO) Piperazine Dioxane Potassium Dipentene Potassium cyanide Dithranol Potassium difluoride Epichlorohydrine Potassium hypochlorite Epoxy reactive diluents Potassium permanganate Ethylene oxide Povidone iodine Ferric chloride hexahydrate Propionic oxide Fluorides Propylene oxide Fluorine Quaternary ammonium compounds Fluoro silicate Reactive diluents Formaldehyde Sodium Gasoline Sodium borohydride Gentian violet Sodium difluoride Glutaraldehyde Sodium hypochlorite Halogenated solvents Sodium sulfite Hexylresorcinol Sodium thiosulfate Iodine Styrene Isocyanates Sulfur dichloride Kerosene fuel Sulfur dioxide Limonene Sulfur mustard Lithium Thioglycollates Lithium chloride Thionyl chloride Mercury compounds Tributyltin oxide Methylchloroisothiazolinone Trichloroethylene Methylenedichloride Turpentine Methylisothiazolinone Vinyl pyridine Morpholine White spirit Perchloroethylene Zinc chloride Peroxides Benzoyl Table 1. Agents causing chemical burns. The chemicals listed Cumene are the most common reported to cause chemical burns in in- dustries, hobbies, and households. The list feature strong corro- Cyclohexanone sive substances and also less irritating compounds that require Hydrogen special conditions, for example occlusion, to cause chemical Methylethylketone burns. Potassium Sodium Phenolic compounds Phosphorus Phosphorus bromides Phosphorus chlorides Phosphorus oxichloride 56 Magnus Bruze, Birgitta Gruvberger, Sigfrid Fregert The most commonly reported chemicals that can penetration is decreased by the barrier formed. Some cause chemical burns are listed in Table 1. Acids common toxic chemicals affect the skin in a special and alkalis have been grouped separately, as the cor- way [26]. Principally, all strong acids give the same rosive effect within the respective group is exerted symptoms and major features, including erythema, through the same mechanism. These groups contain blisters, and necrosis. Some acids discolor the skin, both strong and weak acids and alkalis, respectively. e.g., producing a yellow color from nitric acid. The The other compounds are listed together although action of hydrofluoric acid in the skin differs from their corrosive effects are mediated through different other strong acids [24, 48]. It causes liquefaction ne- mechanisms. Most of these compounds are neutral. crosis, and the penetration may continue for days. However, some are weak acids or alkalis but are con- When an area above 1% of the total body surface is sidered to be corrosive due to properties other than affected, systemic effects can arise. In the skin, this acidity or alkalinity, respectively. acid causes much stronger pains than other acids. Di- luted hydrofluoric acid can cause pain starting several hours or even a day after the exposure. For example, 6.3 Diagnosis when bricklayers use this acid at a concentration of 10%–30% for rinsing brick walls, it may penetrate It is usually easy to arrive at a diagnosis of chemical into their nail beds and, there, cause severe pain after skin burn as the symptoms are easily recognized and several hours. The strong pain is due to the capacity the exposure to a corrosive agent obvious. However, of fluorine ions to bind calcium in the tissue, which sometimes the exposure is concealed, at least initially. affects the nervous system. Hydrofluoric acid can For example, hospital personnel may be exposed penetrate to the bone and cause decalcification there. to ethylene oxide which may remain in gowns and Also, fluorides and fluorosilicic acid can give the same straps after sterilization [5], and cleaners may occa- types of symptoms. sionally be exposed to a corrosive agent contaminat- Alkalis often cause more severe damage than acids, ing nonhazardous objects in a laboratory. Corrosive except hydrofluoric acid [4, 20, 51]. The necrotic skin substances under occlusion may also, at least initially, first appears dark brown and then changes to black. confuse and delay the diagnosis [10]. Chemical skin Later, skin becomes hard, dry, and cracked. Gener- burns caused by skin preparations can be misdiag- ally, no blisters appear in the skin. Alkalis split pro- nosed as electrical burns or pressure sores [32]. Occa- teins and lipids, and there is a saponification of the sionally, a chemical burn can mimic other dermatoses, released fatty acids. The emulsifying effect of the