Irritant contact dermatitis
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Irritant contact dermatitis is a form of contact dermatitis that can be divided into forms caused by chemical irritants and those caused by physical irritants.


Chemical

Chemical irritant contact dermatitis is either acute or chronic, which is usually associated with strong and weak irritants respectively. The following definition is provided by Mathias and Maibach (1978): The mechanism of action varies. Detergents, surfactants, extremes of pH, and organic solvents all directly affecting the barrier properties of the epidermis. These effects include removing fat emulsion,
defatting Degreasing, often called defatting or fat trimming, is the removal of fatty acids from an object. In culinary science, degreasing is done with the intention of reducing the fat content of a meal. Degreasing food Degreasing is often used by diet ...
of dermal lipids, inflicting cellular damage on the epithelium, and increasing the transepidermal water loss by damaging the horny layer water-binding mechanisms and damaging the DNA, which causes the layer to thin. Concentrated irritants have an acute effect, but this is not as common as the accumulative, chronic effect of irritants whose deleterious effects build up with subsequent doses (ESCD 2006). Chemical irritants are often strong
alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...
s as found in drain cleaners and soap with
lye A lye is a metal hydroxide traditionally obtained by leaching wood ashes, or a strong alkali which is highly soluble in water producing caustic basic solutions. "Lye" most commonly refers to sodium hydroxide (NaOH), but historically has been us ...
residues. Many other chemical compounds can also cause contact dermatitis.


Physical

Physical irritant contact dermatitis is a less-researched form of irritant contact dermatitis due to its various mechanisms of action and a lack of a test for its diagnosis. A complete patient history combined with negative allergic patch testing is usually necessary to reach a correct diagnosis. The simplest form of physical irritant contact dermatitis results from prolonged rubbing, although the diversity of implicated irritants is far wider. Examples include paper friction, fiberglass, and scratchy clothing.


Low humidity

Low humidity from
air conditioning Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...
was found to be the most common cause of physical irritant contact dermatitis. To the lay person a definition of low humidity being a ''physical'' irritant can be confusing because low humidity is a deficit (or absence) of an elemental substance, whereas all other irritants implicated in contact dermatitis are in concentrations of relative abundance. So the irritant is actually a lack of water vapour. This confusion is further compounded with the use of the term ''contact'' implying 'touching' (as is the case with all other forms of physical irritant contact dermatitis) whereas in the case of low humidity physical irritant contact dermatitis there is an ''absence of contact'' with water vapour.


Plants

Many
plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
s cause irritant contact dermatitis through their spines or irritant hairs. Some plants such as the
buttercup ''Ranunculus'' is a large genus of about almost 1700 to more than 1800 species of flowering plants in the family Ranunculaceae. Members of the genus are known as buttercups, spearworts and water crowfoots. The genus is distributed in Europe, ...
,
spurge ''Euphorbia'' is a very large and diverse genus of flowering plants, commonly called spurge, in the family Euphorbiaceae. "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae (in deference to t ...
, and daisy act by chemical means. The
sap Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a separa ...
of these plants contains a number of
alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...
s,
glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...
s,
saponin Saponins (Latin "sapon", soap + "-in", one of), also selectively referred to as triterpene glycosides, are bitter-tasting usually toxic plant-derived organic chemicals that have a foamy quality when agitated in water. They are widely distributed ...
s, anthraquinones, and (in the case of plant
bulb In botany, a bulb is structurally a short stem with fleshy leaves or leaf basesBell, A.D. 1997. ''Plant form: an illustrated guide to flowering plant morphology''. Oxford University Press, Oxford, U.K. that function as food storage organs duri ...
s) irritant calcium oxalate crystals - all of which can cause crystal irritant contact dermatitis. Butternut squash and Acorn squash have been known to cause an allergic reaction in many individuals, especially in food preparation where the squash skin is cut and exposed to the epidermis. Food handlers and kitchen workers often take precautions to wear rubber or latex gloves when peeling butternut and acorn squash to avoid temporary Butternut squash ''(Cucurbita moschata)'' dermatitis A contact dermatitis reaction to butternut or acorn squash may result in orange and cracked skin, a sensation of "tightness", "roughness" or "rawness".


Treatment

A humidifier can be used to prevent low indoor humidity during
winter Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultures ...
(especially with indoor heating), and
dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The te ...
.


References


External links

{{DEFAULTSORT:Irritant Contact Dermatitis Contact dermatitis