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Contact dermatitis
Classification and external resources
Rash resulting from wrapping wound (center).
ICD-10 L25.9
ICD-9 692.9
DiseasesDB 29585
eMedicine emerg/131  ped/2569 oph/480
MeSH D003877

Contact dermatitis is a term for a skin reaction resulting from exposure to allergens (allergic contact dermatitis) or irritants (irritant contact dermatitis). The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings L00-L99 - Diseases of the Skin and Subcutaneous tissue (L00-L08 Infections of the Skin and Subcutaneous tissue The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. The Diseases Database is a free Website that provides information about the relationships between medical conditions Symptoms, and Medications. eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books The skin is the outer covering of living tissue of an animal (or plant An allergen is a nonparasitic Antigen capable of stimulating a Type-I hypersensitivity reaction in atopic individuals Irritation or exacerbation, in Biology and Physiology, is a state of Inflammation or painful reaction to Allergy or cell-lining damage Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight. Phototoxicity is a phenomenon known in live-cell where illuminating a fluorescent molecule (the fluorescently active site is called a Fluorophore) causes the selective

Contents

Introduction

Contact dermatitis is a localized rash or irritation of the skin caused by contact with a foreign substance. Only the superficial regions of the skin are affected in contact dermatitis. Inflammation of the affected tissue is present in the epidermis (the outermost layer of skin) and the outer dermis (the layer beneath the epidermis). Epidermis is the outermost layer of the Skin. It forms the waterproof protective wrap over the body's surface and is made up of stratified squamous Epithelium with The dermis is a layer of Skin beneath the epidermis that consists of Connective tissue, and cushions the body from stress and strain [1] Unlike contact urticaria, in which a rash appears within minutes of exposure and fades away within minutes to hours, contact dermatitis takes days to fade away. Even then, contact dermatitis fades only if the skin no longer comes in contact with the allergen or irritant. [2] Contact dermatitis results in large, burning, and itchy rashes, and these can take anywhere from several days to weeks to heal. Chronic contact dermatitis can develop when the removal of the offending agent no longer provides expected relief.

Causes

In North/South America, the most common causes of allergic contact dermatitis are plants of the Toxicodendron genus: poison ivy, poison oak, and poison sumac. Toxicodendron is a genus of woody Trees Shrubs and Vines in the Anacardiaceae or Sumac Family including poison ivy poison oak Toxicodendron diversilobum (syn Rhus diversiloba; Western Poison-oak or Pacific Poison-oak) is a plant best known for its ability to cause Poison sumac ( Toxicodendron vernix or Rhus vernix) is a woody Shrub or small tree growing to 7 m (20 ft tall Common causes of irritant contact dermatitis are harsh (highly alkaline) soaps, detergents, and cleaning products. [3]

Types of contact dermatitis

There are three types of contact dermatitis: irritant contact, allergic contact, and photocontact dermatitis. Photocontact dermatitis is divided into two categories: phototoxic and photoallergic.

Chemical irritant contact dermatitis

is either acute or chronic, which is usually associated with strong and weak irritants respectively (HSE MS24)[4]. The following definition is provided by Mathias and Maibach (1978):[5] a nonimmunologic local inflammatory reaction characterized by erythema, edema, or corrosion following single or repeated application of a chemical substance to an identical cutaneous site.

The mechanism of action varies between toxins. In Pharmacology, the term mechanism of action (MOA refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect Detergents, surfactants, extremes of pH, and organic solvents all have the common effect of directly affecting the barrier properties of the epidermis. These effects include removing fat emulsion, 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. Transepidermal Water Loss (TWL or (TEWL is a term associated with Dermatology and connected sciences Strong concentrations of irritants cause 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).

Common chemical irritants implicated include solvents (alcohol, xylene, turpentine, esters, acetone, ketones, and others); metalworking fluids (neat oils, water-based metalworking fluids with surfactants); latex; kerosene; ethylene oxide; surfactants in topical medications and cosmetics (sodium lauryl sulfate); alkalies (drain cleaners, strong soap with lye residues). o-Xylene|m-Xylene|p-XyleneThe term xylene or xylol refers to a mixture of three Benzene derivatives which is used as a Solvent in the Printing Turpentine (also called spirit of turpentine oil of turpentine wood turpentine gum turpentine is a fluid obtained by the Distillation of Resin obtained from trees Acetone (also known as propanone, dimethyl ketone, 2-propanone, propan-2-one and β-ketopropane) is a colorless mobile flammable A ketone (pronounced as key tone) is either the Functional group characterized by a Carbonyl group (O=C linked to two other Carbon atoms or Kerosene, sometimes spelled kerosine in scientific and industrial usage is a Combustible Hydrocarbon liquid Sodium lauryl sulfate ( SLS) or sodium dodecyl sulfate ( SDS or NaDS ( C 12 H 25 S[[oxygen O]]4 In Chemistry, an alkali (from Arabic: Al-Qaly القلي القالي) is a basic, ionic salt of an Alkali metal Lye is a Corrosive alkaline substance commonly Sodium hydroxide (NaOH

Physical irritant contact dermatitis

is a less researched form of ICD (Maurice-Jones et al)[6] 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. A patch test is a method used to determine if a specific substance causes Inflammation of the Skin. The simplest form of PICD results from prolonged rubbing, although the diversity of implicated irritants is far wider. Examples include paper friction, fiberglass, and scratchy clothing.

low humidity

In a recent analysis of patient data, low humidity from air conditioning was found to be the most common cause of PICD (Morris-Jones, Rachael et al) [7] 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. The term air conditioning refers to the cooling and dehumidification of indoor air for Thermal comfort. So the irritant is actually a lack of another substance, namely water vapour. General properties of water vapor Evaporation/sublimation Whenever a water molecule leaves a surface it is said to have evaporated This confusion is further compounded with the use of the term contact implying 'touching' (as is the case with all other forms of PICD) whereas in the case of low humidity PICD there is an absence of contact with water vapour.

plants

Many plants cause ICD by directly irritating the skin. Plants are living Organisms belonging to the kingdom Plantae. Some plants act through their spines or irritant hairs. Some plant such as the buttercup, spurge, and daisy act by chemical means. Euphorbia is a Genus of Plants belonging to the family Euphorbiaceae. The family Asteraceae or Compositae (known as the aster, daisy, or sunflower family) is the largest family of Flowering The sap of these plants contains a number of alkaloids, glycosides, saponins, anthraquinones, and (in the case of plant bulbs) irritant calcium oxalate crystals - all of which can cause CICD (Mantle and Lennard, 2001)[8]. This article is about the chemical compounds alkaloids For the Pharmaceutical company in the Republic of Macedonia see Alkaloid (company. Saponins are a class of chemical compounds one of very many Secondary metabolites found in natural sources with saponins found in particular abundance in various plant Anthraquinone ( 910-dioxoanthracene) is an aromatic Organic compound. A bulb is an underground vertical Shoot that has modified leaves (or thickened leaf bases that are used as Food Storage organs by An oxalate (also ethanedioate) is a salt or Ester of Oxalic acid.

Allergic Contact Dermatitis

This condition is the manifestation of an allergic response caused by contact with a substance. A list of common allergens is shown in Table 1 (Kucenic and Belsito, 2002)[9].

Although less common than ICD, ACD is accepted to be the most prevalent form of immunotoxicity found in humans (Kimber et al 2002)[10]. By its allergic nature, this form of contact dermatitis is a hypersensitive reaction that is atypical within the population. The mechanisms by which these reactions occur are complex, with many levels of fine control. Their immunology centres around the interaction of immunoregulatory cytokines and discrete subpopulations of T lymphocytes. Cytokines are a category of signalling Proteins and Glycoproteins that like Hormones and Neurotransmitters, are used extensively in cellular

ACD arises as a result of two essential stages: an induction phase, which primes and sensitizes the immune system for an allergic response, and an elicitation phase, in which this response is triggered (Kimble et al 2002). As such, ACD is termed a Type IV delayed hypersensitivity reaction involving a cell-mediated allergic response. Contact allergens are essentially soluble haptens (low in molecular weight) and, as such, have the physico-chemical properties that allow them to cross the stratum corneum of the skin. A hapten is a Small molecule which can elicit an immune response only when attached to a large carrier such as a Protein; the carrier may be one which also does not They can only cause their response as part of a complete antigen, involving their association with epidermal proteins forming hapten-protein conjugates. An antigen (from antibody-generating) or immunogen is a substance that prompts the generation of Antibodies and can cause an immune response This, in turn, requires them to be protein-reactive.

The conjugate formed is then recognized as a foreign body by the Langerhans cells (LCs) (and in some cases Dendritic cells (DCs)), which then internalize the protein; transport it via the lymphatic system to the regional lymph nodes; and present the antigen to T-lymphocytes. Not to be confused with the Beta cells making up the Islets of Langerhans. Dendritic cells (DCs are Immune cells and form part of the Mammalian Immune system. The lymphatic system in Vertebrates is a network of conduits that carry a clear fluid called Lymph. A Lymph node ( lɪmf noʊd is an organ consisting of many types of cells and is a part of the Lymphatic system. This process is controlled by cytokines and chemokines - with tumor necrosis factor alpha (TNF-α) and certain members of the interleukin family (1, 13 and 18) - and their action serves either to promote or to inhibit the mobilization and migration of these LCs. (Kimble et al 2002) As the LCs are transported to the lymph nodes, they become differentiated and transform into DCs, which are immunostimulatory in nature.

Once within the lymph glands, the differentiated DCs present the allergenic epitope associated with the allergen to T lymphocytes. These T cells then divide and differentiate, clonally multiplying so that if the allergen is experienced again by the individual, these T cells will respond more quickly and more aggressively.

Kimbe et al (2002) explore the complexities of ACD's immunological reaction in short: It appears that there are two major phenotypes of cytokine production (although there exists a gradient of subsets in between), and these are termed T-helper 1 and 2 (Th1 and Th2). Although these cells initially differentiate from a common stem cell, they develop with time as the immune system matures. Stem cells are cells found in most if not all multi-cellular Organisms. Th1 phenotypes are characterised by their focus on Interleukin and Interferon, while Th2 cells action is centred more around the regulation of IgE by cytokines. The CD4 and CD8 T lymphocyte subsets also have been found to contribute to differential cytokine regulation, with CD4 having been shown to produce high levels of IL-4 and IL10 while solely CD8 cells are associated with low levels of IFN?. These two cell subtypes are also closely associated with the cell matrix interactions essential for the pathogenesis of ACD.

White et al have suggested that there appears to be a threshold to the mechanisms of allergic sensitisation by ACD-associated allergens (1986). [11] This is thought to be linked to the level at which the toxin induces the up-regulation of the required mandatory cytokines and chemokines. It has also been proposed that the vehicle in which the allergen reaches the skin could take some responsibility in the sensitisation of the epidermis by both assisting the percutaneous penetration and causing some form of trauma and mobilization of cytokines itself.

Common allergens implicated include the following:

Photocontact Dermatitis

Sometimes termed "photoaggravated"(Bourke et al 2001)[14], and divided into two categories, phototoxic and photoallergic, PCD is the eczematous condition which is triggered by an interaction between an otherwise unharmful or less harmful substance on the skin and ultraviolet light (320-400nm UVA) (ESCD 2006), therefore manifesting itself only in regions where the sufferer has been exposed to such rays. Without the presence of these rays, the photosensitiser is not harmful. For this reason, this form of contact dermatitis is usually associated only with areas of skin which are left uncovered by clothing. The mechanism of action varies from toxin to toxin, but is usually due to the production of a photoproduct. Toxins which are associated with PCD include the psoralens. Psoralens are in fact used therapeutically for the treatment of psoriasis, eczema and vitiligo.

Photocontact dermatitis is another condition where the distinction between forms of contact dermatitis is not clear cut. Immunological mechanisms can also play a part, causing a response similar to ACD.

Symptoms

Allergic dermatitis is usually confined to the area where the trigger actually touched the skin, whereas irritant dermatitis may be more widespread on the skin. Symptoms of both forms include the following:

While either form of contact dermatitis can affect any part of the body, irritant contact dermatitis often affects the hands, which have been exposed by resting in or dipping into a container (sink, pail, tub, Sun, Swimming Pools With High chlorine ), containing the irritant.

Treatment

Self-care at Home

- Weak acid solutions [lemon juice, vinegar] can be used to counteract the effects of dermatitis contracted by exposure to basic irritants [phenol etc. In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and ].

Medical Care

If the rash does not improve or continues to spread after 2-3 of days of self-care, or if the itching and/or pain is severe, the patient should contact a dermatologist or other physician. Dermatology (from Greek grc δέρμα derma, "skin" and grc -λογία -logia) is a branch of Medicine dealing with A physician, medical practitioner or medical doctor who practices Medicine, and is concerned with maintaining or restoring human Health Medical treatment usually consists of lotions, creams, or oral medications.

Prevention

Since contact dermatitis relies on an irritant or an allergen to initiate the reaction, it is important for the patient to identify the responsible agent and avoid it. This can be accomplished by having patch tests, a method commonly known as allergy testing. The patient must know where the irritant or allergen is found to be able to avoid it. It is important to also note that chemicals sometimes have several different names. [15]

Summary

The distinction between the various types of contact dermatitis is based on a number of factors. The morphology of the tissues, the histology, and immunologic findings are all used in diagnosis of the form of the condition. However, as suggested previously, there is some confusion in the distinction of the different forms of contact dermatitis (Reitschel 1997)[16]. Using histology on its own is insufficient, as these findings have been acknowledged not to distinguish (Rietschel, 1997), and even positive patch testing does not rule out the existence of an irritant form of dermatitis as well as an immunological one. It is important to remember, therefore, that the distinction between the types of contact dermatitis is often blurred, with, for example, certain immunological mechanisms also being involved in a case of irritant contact dermatitis.

References

  1. ^ ESDC. What is contact dermatitis. European Society of Contact Dermatitis, http://orgs.dermis.net
  2. ^ DermNet NZ: Contact Dermatitis. Retrieved on 2006-08-14. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1183 - Taira no Munemori and the Taira clan take the young Emperor Antoku and the three sacred treasures
  3. ^ Irritant Contact Dermatitis, at DermNetNZ, http://www.dermnetnz.org/dermatitis/contact-irritant.html
  4. ^ HSE Guidance Notes. Guidance Note MS 24 - Health Surveillance of occupational skin disease. http://www.hse.gov.uk/pubns/ms24.pdf
  5. ^ Mathias CG, Maibach HI. Dermatotoxicology monographs I. Cutaneous irritation: factors influencing the response to irritants. Clin Toxicol. 1978;13(3):333-46. Review. No abstract available.
  6. ^ Morris-Jones R, Robertson SJ, Ross JS, White IR, McFadden JP, Rycroft RJ. Dermatitis caused by physical irritants. Br J Dermatol. 2002 Aug;147(2):270- 5. Review.
  7. ^ Dermatitis caused by physical irritants. British Journal Dermatology Vol. 147 Issue 2 Page 270 August 2002. Morris-Jones R, Robertson SJ, Ross JS, White IR, McFadden JP, Rycroft RJ. http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&term=12174098
  8. ^ Mantle D, Lennard TWJ. Plants and the skin. Brit J Derm Nurs. 2001 (Summer).
  9. ^ Kucenic MJ, Belsito DV. Occupational allergic contact dermatitis is more prevalent than irritant contact dermatitis: a 5-year study. J Am Acad Dermatol. 2002 May;46(5):695-9.
  10. ^ Kimber I, Basketter DA, Gerberick GF, Dearman RJ. Allergic contact dermatitis. Int Immunopharmacol. 2002 Feb;2(2-3):201-11. Review.
  11. ^ White SI, Friedmann PS, Moss C, Simpson JM. The effect of altering area of application and dose per unit area on sensitization by DNCB. Br J Dermatol. 1986 Dec;115(6):663-8.
  12. ^ Allergy to fragrance mix at DermNetNZ, http://dermnetnz.org/dermatitis/fragrance-allergy.html
  13. ^ Mayo Clinic study, http://www.mayoclinic.org/news2006-rst/3268.html
  14. ^ Bourke J, Coulson I, English J; British Association of Dermatologists. Guidelines for care of contact dermatitis. Br J Dermatol. 2001 Dec;145(6):877-85.
  15. ^ DermNet dermatitis/contact-allergy
  16. ^ Rietschel RL. The New Zealand Dermatological Society is a medical organization best known outside New Zealand for its "DermNet" website which provides photographs and descriptions Mechanisms in irritant contact dermatitis. Clin Dermatol. 1997 Jul-Aug;15(4):557-9.

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