{{Short description|Inflammation from allergen or irritant exposure}} {{Infobox medical condition (new) | name = Contact dermatitis | synonyms = | image = Contact_dermatitis_around_wound.jpg | caption = Contact dermatitis rash. | pronounce = | field = Dermatology | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }}
<!-- Definition and symptoms --> '''Contact dermatitis''' is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents.<ref name=":1"/> Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are not contagious or life-threatening, but can be very uncomfortable.
<!-- Cause and diagnosis --> Contact dermatitis results from either exposure to allergens (allergic contact dermatitis), or irritants (irritant contact dermatitis). Allergic contact dermatitis involves a delayed type of hypersensitivity and previous exposure to an allergen to produce a reaction.<ref>{{Cite journal |last1=Cohen |first1=David E. |last2=Heidary |first2=Noushin |date=September 2004 |title=Treatment of irritant and allergic contact dermatitis |journal=Dermatologic Therapy |language=en |volume=17 |issue=4 |pages=334–340 |doi=10.1111/j.1396-0296.2004.04031.x |pmid=15327479 |s2cid=42322170 |issn=1396-0296|doi-access=free }}</ref> Irritant contact dermatitis is the most common type and represents 80% of all cases.<ref name=":1">{{Cite journal |last1=Bains |first1=Sonia N. |last2=Nash |first2=Pembroke |last3=Fonacier |first3=Luz |date=2019-02-01 |title=Irritant Contact Dermatitis |url=https://doi.org/10.1007/s12016-018-8713-0 |journal=Clinical Reviews in Allergy & Immunology |language=en |volume=56 |issue=1 |pages=99–109 |doi=10.1007/s12016-018-8713-0 |pmid=30293200 |s2cid=52931782 |issn=1559-0267|url-access=subscription }}</ref> It is caused by prolonged exposure to irritants, leading to direct injury of the epidermal cells of the skin, which activates an immune response, resulting in an inflammatory cutaneous reaction.<ref name=":1" /> Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight. Diagnosis of allergic contact dermatitis can often be supported by patch testing.<ref name="Tramontana"/><ref name="Sukakul">{{cite journal |last1=Sukakul |first1=T |last2=Svedman |first2=C |title=What is New in Contact Allergy To Cosmetics for Physicians, Cosmetologists, and Cosmetic Users? |journal=Current Allergy and Asthma Reports |date=24 October 2025 |volume=25 |issue=1 |pages=48 |doi=10.1007/s11882-025-01226-5 |pmid=41134517 |pmc=12552389 }}</ref><ref>{{cite journal | vauthors = Mowad CM | title = Contact Dermatitis: Practice Gaps and Challenges | journal = Dermatologic Clinics | volume = 34 | issue = 3 | pages = 263–267 | date = July 2016 | pmid = 27363882 | doi = 10.1016/j.det.2016.02.010 }}</ref>
==Epidemiology== Metanalysis of research on the incidence and prevalence of contact dermatitis suggests that as much as 20% of the general population is contact‐allergic to patch tests for common environmental allergens. Prevalence is lower in people under 18 years of age, and higher in women than in men.<ref>{{cite journal |last1=Aristizabal-Torres |first1=MA |last2=Bruce |first2=CJ |last3=Caruso |first3=MA |last4=Wieczorek |first4=MA |last5=Pacheco-Spann |first5=LM |last6=Carter |first6=RE |last7=Bruce |first7=AJ |last8=Hall |first8=MR |title=Allergic contact dermatitis revisited: A comprehensive review |journal=JAAD Reviews |date=1 June 2025 |volume=4 |pages=92–103 |doi=10.1016/j.jdrv.2025.03.011 |issn=2950-1989|doi-access=free }}</ref><ref name="Alinaghi">{{cite journal |last1=Alinaghi |first1=F |last2=Bennike |first2=NH |last3=Egeberg |first3=A |last4=Thyssen |first4=JP |last5=Johansen |first5=JD |title=Prevalence of contact allergy in the general population: A systematic review and meta-analysis. |journal=Contact Dermatitis |date=February 2019 |volume=80 |issue=2 |pages=77–85 |doi=10.1111/cod.13119 |pmid=30370565}}</ref> Contact dermatitis constitutes 90%<ref name="Tramontana"/> to 95% of all occupational skin disorders.<ref>{{cite journal | vauthors = Bains SN, Nash P, Fonacier L | title = Irritant Contact Dermatitis | journal = Clinical Reviews in Allergy & Immunology | volume = 56 | issue = 1 | pages = 99–109 | date = February 2019 | pmid = 30293200 | doi = 10.1007/s12016-018-8713-0 | s2cid = 52931782 }}</ref>
==Signs and symptoms== 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).<ref>{{cite web|url=http://orgs.dermis.net/|title= What is contact dermatitis|author= European Society of Contact Dermatitis}}</ref>
Contact dermatitis results in large, burning, and itchy rashes. These can take anywhere from several days to weeks to heal. This differentiates it from contact urticaria (hives), in which a rash appears within minutes of exposure and then fades away within minutes to hours. Even after days, contact dermatitis fades only if the skin no longer comes in contact with the allergen or irritant.<ref>{{cite web|url=http://www.dermnetnz.org/dermatitis/contact-allergy.html|title=DermNet NZ: Contact Dermatitis| access-date = 2006-08-14 }}</ref> If contact dermatitis lasts for more than six weeks, either because exposure continues or the skin can't recover, it can be referred to as chronic.<ref>{{cite web |title=Can Contact Dermatitis Become Chronic? What You Should Know |url=https://www.dermdoctorsnva.com/blog/1348951-can-contact-dermatitis-become-chronic-what-you-should-know/ |website=Dermatology & Dermatologic Surgery Group of Northern Virginia, PLLC}}</ref><ref name="Novak-Bilić" />
Irritant dermatitis is usually confined to the area where the irritating substance actually touched the skin, whereas allergic dermatitis may be more widespread on the skin. Irritant dermatitis is usually found on hands. Airborne irritant contact dermatitis can occur when airborne irritants come into contact with exposed areas of skin.<ref name="Patel">{{cite journal |last1=Patel |first1=K |last2=Nixon |first2=R |title=Irritant Contact Dermatitis - a Review. |journal=Current Dermatology Reports |date=2022 |volume=11 |issue=2 |pages=41–51 |doi=10.1007/s13671-021-00351-4 |pmid=35433115 |pmc=8989112 }}</ref> Symptoms of both irritant and allergic dermatitis include the following:
* '''Red rash:''' This is the usual reaction. The rash appears immediately in irritant contact dermatitis;<ref name="Patel" /> in allergic contact dermatitis, the rash tends to appear 24–72 hours after exposure to the allergen.<ref name="Tramontana"/><ref name="Gkagkari">{{cite journal |last1=Gkagkari |first1=P |last2=Tagka |first2=A |last3=Stratigos |first3=A |last4=Karalis |first4=V |last5=Kyritsi |first5=A |last6=Vitsos |first6=A |last7=Rallis |first7=MC |title=Differential Diagnosis of Irritant Versus Allergic Contact Dermatitis Based on Noninvasive Methods. |journal=Dermatology Practical & Conceptual |date=30 October 2024 |volume=14 |issue=4 |pages=e2024231 |article-number=11 |doi=10.5826/dpc.1404a231 |pmid=39652964 |pmc=11619931 }}</ref> * '''Itchy, burning skin:''' Irritant contact dermatitis tends to be more painful than itchy, while allergic contact dermatitis often itches.<ref name="Tramontana"/> * '''Blisters or wheals:''' Blisters (bullae), wheals (welts), and urticaria (hives) often form in a pattern where skin was directly exposed to the allergen or irritant.<ref name="Patel" /><ref name="Tramontana" /> * '''The surface appearance of skin:''' Skin is dry and fissured in the irritant contact dermatitis<ref name="Novak-Bilić">{{cite journal |last1=Novak-Bilić |first1=G |last2=Vučić |first2=M |last3=Japundžić |first3=I |last4=Meštrović-Štefekov |first4=J |last5=Stanić-Duktaj |first5=S |last6=Lugović-Mihić |first6=L |title=Irritant and Allergic Contact Dermatitis – Skin Lesion Characteristics |journal=Acta Clinica Croatica |date=December 2018 |volume=57 |issue=4 |pages=713–720 |doi=10.20471/acc.2018.57.04.13 |pmid=31168208 |pmc=6544100 }}</ref> whereas vesicles and bullae are seen in allergic contact dermatitis.<ref name="Tramontana"/><ref>{{Cite journal |last=RAJAGOPALAN |first=R |date=September 1998 |title=An economic evaluation of patch testing in the diagnosis and management of allergic contact dermatitis*1 |url=http://dx.doi.org/10.1016/s1046-199x(98)90017-3 |journal=American Journal of Contact Dermatitis |volume=9 |issue=3 |pages=149–154 |doi=10.1016/s1046-199x(98)90017-3 |pmid=9744907 |issn=1046-199X|url-access=subscription }}</ref> * '''Lichenified lesions:'''<ref name=":1" /><ref name="Tramontana"/><ref name="Novak-Bilić"/>
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 containing an irritant. Common irritants include water, soaps, solvents, and detergents.<ref name="Tramontana"/><ref name="Novak-Bilić"/>
== Causes == The percentage of cases attributable to occupational contact dermatitis varies substantially depending on the industries that predominate, the employment that people have, the risks to which they are exposed, the centers that record cases, and variances in defining and confirming diagnoses.<ref>{{Cite journal |last=Nicholson |first=Paul J. |date=May 2011 |title=Occupational contact dermatitis: Known knowns and known unknowns |url=http://dx.doi.org/10.1016/j.clindermatol.2010.11.012 |journal=Clinics in Dermatology |volume=29 |issue=3 |pages=325–330 |doi=10.1016/j.clindermatol.2010.11.012 |pmid=21496742 |issn=0738-081X|url-access=subscription }}</ref>
Common causes of allergic contact dermatitis include: nickel allergy, 14K or 18K gold, Balsam of Peru (''Myroxylon pereirae''), and chromium. In the Americas they include the oily, urushiol-containing coating from plants of the genus ''Toxicodendron'': poison ivy, poison oak, and poison sumac. Millions of cases occur each year in North America alone.<ref name="glad">{{cite journal | vauthors = Gladman AC | title = Toxicodendron dermatitis: poison ivy, oak, and sumac | journal = Wilderness & Environmental Medicine | volume = 17 | issue = 2 | pages = 120–128 | year = 2006 | pmid = 16805148 | doi = 10.1580/pr31-05.1 | doi-access = free }}</ref> The alkyl resorcinols in ''Grevillea banksii'' and ''Grevillea'' 'Robyn Gordon' are responsible for contact dermatitis.<ref>{{cite journal | vauthors = Menz J, Rossi ER, Taylor WC, Wall L | title = Contact dermatitis from Grevillea 'Robyn Gordon' | journal = Contact Dermatitis | volume = 15 | issue = 3 | pages = 126–131 | date = September 1986 | pmid = 2946534 | doi = 10.1111/j.1600-0536.1986.tb01311.x | s2cid = 2846186 }}</ref> Bilobol, another alkyl resorcinol found in ''Ginkgo biloba'' fruits, is also a strong skin irritant.<ref>{{cite journal | vauthors = Matsumoto K, Fujimoto M, Ito K, Tanaka H, Hirono I | title = Comparison of the effects of bilobol and 12-O-tetradecanoylphorbol-13-acetate on skin, and test of tumor promoting potential of bilobol in CD-1 mice | journal = The Journal of Toxicological Sciences | volume = 15 | issue = 1 | pages = 39–46 | date = February 1990 | pmid = 2110595 | doi = 10.2131/jts.15.39 | doi-access = free }}</ref>
Common causes of irritant contact dermatitis include solvents, metalworking fluids, latex, kerosene, ethylene oxide, paper, especially papers coated with chemicals and printing inks, certain foods and drink,<ref name="dermnetnz1">{{cite web|url=http://www.dermnetnz.org/dermatitis/balsam-of-peru-allergy.html |title=Balsam of Peru contact allergy. |publisher=DermNet NZ |date=2013-12-28 |access-date=2014-04-17}}</ref> food flavorings and spices,<ref>{{cite web | vauthors = Taylor JS, Amado A |url=http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/dermatology/contact-dermatitis-and-related-conditions/ | archive-url = https://web.archive.org/web/20120725083236/http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/dermatology/contact-dermatitis-and-related-conditions/ | archive-date = 25 July 2012 |title=Contact Dermatitis and Related Conditions |publisher=Clevelandclinicmeded.com |access-date=2014-04-17}}</ref> perfumes and other fragrances used in cosmetics and cleaning products,<ref name="Rana">{{cite journal |last1=Rana |first1=P |last2=Pathania |first2=D |last3=Gaur |first3=P |last4=Patel |first4=SK |last5=Bajpai |first5=M |last6=Singh |first6=NT |last7=Pandey |first7=R |last8=Shukla |first8=SV |last9=Pant |first9=AB |last10=Ray |first10=RS |last11=Dwivedi |first11=A |title=Regulatory frameworks for fragrance safety in cosmetics: a global overview. |journal=Toxicological Research |date=May 2025 |volume=41 |issue=3 |pages=199–220 |doi=10.1007/s43188-025-00283-2 |pmid=40291114 |pmc=12021755 |bibcode=2025ToxRe..41..199R }}</ref><ref name="dermnetnz1"/> surfactants in topical medications and cosmetics, alkalis, low humidity from air conditioning, and many plants. Other common causes of irritant contact dermatitis are harsh alkaline soaps, detergents, and cleaning products.<ref>[http://www.dermnetnz.org/dermatitis/contact-irritant.html Irritant Contact Dermatitis.] DermNetNZ.org</ref>
There are four types of contact dermatitis: irritant contact dermatitis; allergic contact dermatitis; protein contact dermatitis; and photo contact dermatitis. Photo contact dermatitis is divided into two categories: phototoxic and photoallergic.<ref name="Tramontana">{{cite journal |last1=Tramontana |first1=M |last2=Hansel |first2=K |last3=Bianchi |first3=L |last4=Sensini |first4=C |last5=Malatesta |first5=N |last6=Stingeni |first6=L |title=Advancing the understanding of allergic contact dermatitis: from pathophysiology to novel therapeutic approaches. |journal=Frontiers in Medicine |date=2023 |volume=10 |article-number=1184289 |doi=10.3389/fmed.2023.1184289 |doi-access=free |pmid=37283623 |pmc=10239928 }}</ref>
===Irritant contact dermatitis=== {{Main|Irritant contact dermatitis}}
The irritant's direct cytotoxic impact on epidermal keratinocytes causes Irritant contact dermatitis.<ref name=":1" /> This disrupts the skin barrier and activates the innate immune system. Keratinocytes in the epidermis can be actually affected by irritants.<ref name=":1" /> It is a complicated reaction that is influenced by genetic and environmental elements, both of which have a role in the pathogenesis of the disease.<ref name=":1" /> It can be seen in both occupational and non-occupational environments but it's more common in the occupations dealing in low humidity conditions.<ref name=":1" />[[File:Contact_dermatitis.jpg|thumb|Contact dermatitis caused by unprotected handling of damp, impregnated wooden construction debris.]] Irritant contact dermatitis (ICD) can be divided into forms caused by chemical irritants, and those caused by physical irritants. 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); and alkalis (drain cleaners, strong soap with lye residues).{{citation needed|date=May 2024}}
Physical irritant contact dermatitis may most commonly be caused by low humidity from air conditioning.<ref name=Morris>{{cite journal | vauthors = Morris-Jones R, Robertson SJ, Ross JS, White IR, McFadden JP, Rycroft RJ | title = Dermatitis caused by physical irritants | journal = The British Journal of Dermatology | volume = 147 | issue = 2 | pages = 270–275 | date = August 2002 | pmid = 12174098 | doi = 10.1046/j.1365-2133.2002.04852.x | s2cid = 8444176 }}</ref> Also, many plants directly irritate the skin.
===Allergic contact dermatitis=== {{Main|Allergic contact dermatitis}}
thumb|Three-year-old girl with contact dermatitis, one day after contact with poison ivy
Allergic contact dermatitis (ACD) is accepted to be the most prevalent form of immunotoxicity found in humans, and is a common occupational and environmental health problem.<ref name=":2">{{cite journal | vauthors = Kimber I, Basketter DA, Gerberick GF, Dearman RJ | title = Allergic contact dermatitis | journal = International Immunopharmacology | volume = 2 | issue = 2–3 | pages = 201–211 | date = February 2002 | pmid = 11811925 | doi = 10.1016/S1567-5769(01)00173-4 }}</ref> By its allergic nature, this form of contact dermatitis is a hypersensitive reaction that is atypical within the population. The development of the disease occurs in two phases, which are induction and elicitation.<ref name=":2" /> The process of skin sensitization begins when a susceptible subject is exposed to the allergen in sufficient concentration to elicit the required cutaneous immune response. This causes sensitization and when exposure to the same allergen at a later time at the same or different skin site leads to a secondary immune response at the point of contact.<ref name=":2" /> The mechanisms by which this reaction occurs are complex, with many levels of fine control. Their immunology centres on the interaction of immunoregulatory cytokines and discrete subpopulations of T lymphocytes.{{citation needed|date=May 2024}}
Allergens include nickel, gold, Balsam of Peru (''Myroxylon pereirae''), chromium, and the oily coating from plants of the genus ''Toxicodendron'', such as poison ivy, poison oak, and poison sumac. Acrylates, rubber chemicals, emulsifiers and dyes, epoxy resin chemicals are just several of the substances that might induce Allergic Contact Dermatitis.<ref name=":2" /> Much of the allergic contact dermatitis that arises is caused by occupational exposure. Non-occupational exposure to allergens in medicaments, clothing, cosmetics, and plants are also a significant cause of allergic contact dermatitis.<ref name=":2" />
===Photocontact dermatitis=== {{Main|Phytophotodermatitis}}
Sometimes termed "photoaggravated",<ref>{{cite journal | vauthors = Bourke J, Coulson I, English J | title = Guidelines for care of contact dermatitis | journal = The British Journal of Dermatology | volume = 145 | issue = 6 | pages = 877–885 | date = December 2001 | pmid = 11899139 | doi = 10.1046/j.1365-2133.2001.04499.x | s2cid = 26038634 }}</ref> and divided into two categories, phototoxic and photoallergic, PCD is the eczematous condition which is triggered by an interaction between a substance on the skin and ultraviolet light<ref name="Tramontana"/><ref name="Jacobsen">{{cite journal |last1=Jacobsen |first1=G |last2=Rasmussen |first2=K |last3=Bregnhøj |first3=A |last4=Isaksson |first4=M |last5=Diepgen |first5=TL |last6=Carstensen |first6=O |title=Causes of irritant contact dermatitis after occupational skin exposure: a systematic review. |journal=International Archives of Occupational and Environmental Health |date=January 2022 |volume=95 |issue=1 |pages=35–65 |doi=10.1007/s00420-021-01781-0 |pmid=34665298 |pmc=8755674 |bibcode=2022IAOEH..95...35J }}</ref> (320–400 nm UVA) (ESCD 2006), therefore manifesting itself only in regions where the affected person has been exposed to such rays.{{citation needed|date=May 2024}}
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 that are left uncovered by clothing, and it can be soundly defeated by avoiding exposure to sunlight.<ref>{{cite web|title=Photocontact Dermatitis|url=http://skinchannel.com/dermatitis/photocontact-dermatitis/|work=www.skinchannel.com|access-date=31 March 2011|archive-date=21 April 2011|archive-url=https://web.archive.org/web/20110421023207/http://skinchannel.com/dermatitis/photocontact-dermatitis/|url-status=dead}}</ref> 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.{{citation needed|date=May 2024}}
Photocontact dermatitis is another condition in which the distinction between forms of contact dermatitis is not clear-cut. Immunological mechanisms can also play a part, causing a response similar to ACD.
=== Protein contact dermatitis === Protein contact dermatitis (PCD) is a form of chronic eczema resulting from immediate hypersensitivity to plant, animal, or hydrolized proteins. It is most frequently seen in occupational settings involving food handling. PCD is diagnosed by prick tests.<ref name="Barbaud">{{cite journal |last1=Barbaud |first1=A |title=Mechanism and diagnosis of protein contact dermatitis. |journal=Current Opinion in Allergy and Clinical Immunology |date=April 2020 |volume=20 |issue=2 |pages=117–121 |doi=10.1097/ACI.0000000000000621 |pmid=31972603}}</ref><ref>{{cite book |last1=Goossens |first1=A |last2=Amaro |first2=C |last3=Mahler |first3=V |title=Contact Dermatitis |date=2021 |publisher=Springer, Cham |isbn=978-3-030-36335-2 |pages=355–364 |chapter-url=https://doi.org/10.1007/978-3-030-36335-2_21 |language=en |chapter=Protein Contact Dermatitis |doi=10.1007/978-3-030-36335-2_21 }}</ref><ref>{{cite journal |last1=Ashbaugh |first1=AG |last2=Abel |first2=MK |last3=Murase |first3=JE |title=Protein Causes of Urticaria and Dermatitis. |journal=Immunology and Allergy Clinics of North America |date=August 2021 |volume=41 |issue=3 |pages=481–491 |doi=10.1016/j.iac.2021.04.008 |pmid=34225902}}</ref>
==Diagnosis== [[File:Epikutanni-test.jpg|thumb|Patch test]]
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, one of various methods commonly known as allergy testing.<ref name="Tramontana"/> The patch tests were based on the concept of a type IV hypersensitivity reaction where there is exposure of allergens to skin and checking for the development of contact dermatitis in that area. This test involves the application of suspected irritant to a part of the skin and cover it with impermeable material and attached to the skin with the help of adhesive plaster.<ref>{{Cite journal |last1=Schwartz |first1=Louis |last2=Peck |first2=Samuel M. |date=1944 |title=The Patch Test in Contact Dermatitis |url=https://www.jstor.org/stable/4584864 |journal=Public Health Reports |language=en |volume=59 |issue=17 |pages=546 |doi=10.2307/4584864|jstor=4584864 |url-access=subscription }}</ref> The top three allergens found in patch tests from 2005 to 2006 were: nickel sulfate (19.0%), Myroxylon pereirae (Balsam of Peru, 11.9%), and fragrance mix I (11.5%).<ref name="autogenerated2005">{{cite journal | vauthors = Zug KA, Warshaw EM, Fowler JF, Maibach HI, Belsito DL, Pratt MD, Sasseville D, Storrs FJ, Taylor JS, Mathias CG, Deleo VA, Rietschel RL, Marks J | display-authors = 6 | title = Patch-test results of the North American Contact Dermatitis Group 2005-2006 | journal = Dermatitis | volume = 20 | issue = 3 | pages = 149–160 | year = 2009 | pmid = 19470301 | doi = 10.2310/6620.2009.08097 | s2cid = 24088485 }}</ref> 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, and do not always appear on labels.<ref>{{DermNet|dermatitis/contact-allergy}}</ref>
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.<ref name="rietschel1997">{{cite journal | vauthors = Rietschel RL | title = Mechanisms in irritant contact dermatitis | journal = Clinics in Dermatology | volume = 15 | issue = 4 | pages = 557–559 | year = 1997 | pmid = 9255462 | doi = 10.1016/S0738-081X(97)00058-8 }}</ref> Using histology on its own is insufficient, as these findings have been acknowledged not to distinguish,<ref name="rietschel1997"/> and even positive patch testing does not rule out the existence of an irritant form of dermatitis as well as an immunological one.
==Prevention== In an industrial setting the employer has a duty of care to its worker to provide the correct level of safety equipment to mitigate exposure to harmful irritants. This can take the form of protective clothing, gloves, or barrier cream, depending on the working environment. It is impossible to eliminate the complete exposure to harmful irritants but can be avoided using the multidimensional approach. The multidimensional approach includes eight basic elements to follow. They are:
* Identification of possible cutaneous irritants and allergens * To avoid skin exposure, use appropriate control measures or chemical substitutes. * Personal protection can be achieved by the use of protective clothes or barrier creams. * Maintenance of personal and environmental hygiene * Use of harmful irritants in the workplace should be regulated * Efforts to raise knowledge of potential allergies and irritants through education * Promoting safe working conditions and practices * Health screenings before and after employment and on a regular basis<ref>{{Cite journal |last=Mathias |first=C.G. Toby |date=October 1990 |title=Prevention of occupational contact dermatitis |url=http://dx.doi.org/10.1016/0190-9622(90)70284-o |journal=Journal of the American Academy of Dermatology |volume=23 |issue=4 |pages=742–748 |doi=10.1016/0190-9622(90)70284-o |pmid=2146291 |issn=0190-9622|url-access=subscription }}</ref>
Topical antibiotics should not be used to prevent infection in wounds after surgery.<ref name="AADfive">{{Citation |author1 = American Academy of Dermatology |author1-link = American Academy of Dermatology |date = February 2013 |title = Five Things Physicians and Patients Should Question |publisher = American Academy of Dermatology |work = Choosing Wisely: an initiative of the ABIM Foundation |url = http://www.choosingwisely.org/doctor-patient-lists/american-academy-of-dermatology/ |access-date = 5 December 2013}}</ref><ref>{{cite journal | vauthors = Sheth VM, Weitzul S | title = Postoperative topical antimicrobial use | journal = Dermatitis | volume = 19 | issue = 4 | pages = 181–189 | year = 2008 | pmid = 18674453 | doi = 10.2310/6620.2008.07094 }}</ref> When they are used, it is inappropriate, and the person recovering from surgery is at significantly increased risk of developing contact dermatitis.<ref name="AADfive" />
==Treatment== ===Self-care=== * If blistering develops, cold moist compresses<ref name="mayoclinic1">{{cite web|url=http://www.mayoclinic.org/diseases-conditions/contact-dermatitis/basics/lifestyle-home-remedies/con-20032048 |title=Contact dermatitis Lifestyle and home remedies – Diseases and Conditions |publisher=Mayo Clinic |date=2011-07-30 |access-date=2014-04-18}}</ref> applied for 30 minutes, three times a day can offer relief. * Calamine lotion may relieve itching.<ref name="mayoclinic1"/> * Oral antihistamines such as diphenhydramine (Benadryl, Ben-Allergin) can relieve itching.<ref name="mayoclinic1"/> * Avoid scratching.<ref name="mayoclinic1"/> * Immediately after exposure to a known allergen or irritant, wash with soap and cool water to remove or inactivate most of the offending substance. * For mild cases that cover a relatively small area, hydrocortisone cream in nonprescription strength may be sufficient. * Weak acid solutions (lemon juice, vinegar) can be used to counteract the effects of dermatitis contracted by exposure to basic irritants. * A barrier cream, such as those containing zinc oxide (''e.g.'', Desitin, etc.), may help protect the skin and retain moisture.
===Medical care=== If the rash does not improve or continues to spread after two to three of days of self-care, or if the itching and/or pain is severe, the patient should contact a dermatologist or other physician. Medical treatment usually consists of lotions, creams, or oral medications.
* '''Corticosteroids'''. A corticosteroid medication like hydrocortisone may be prescribed to combat inflammation in a localized area. It may be applied to the skin as a cream or ointment. If the reaction covers a relatively large portion of the skin or is severe, a corticosteroid in pill or injection form may be prescribed.
In severe cases, a stronger medicine like halobetasol may be prescribed by a dermatologist.
* '''Antihistamines'''. Prescription antihistamines may be given if non-prescription strengths are inadequate.
== See also == * {{annotated link|Eczema}} * {{annotated link|Hock burns}} * {{annotated link|Nickel allergy}} * {{annotated link|Urushiol-induced contact dermatitis}}
== References == {{Reflist}}
== External links == {{Commons category|Contact dermatitis}} * [http://www.emedicinehealth.com/contact_dermatitis/article_em.htm eMedicine Health article on contact dermatitis]
{{Medical resources | DiseasesDB = 29585 | ICD10 = {{ICD10|L|25|9|l|20}} | ICD9 = {{ICD9|692.9}} | ICDO = | OMIM = | MedlinePlus = 000869 | eMedicineSubj = emerg | eMedicineTopic = 131 | eMedicine_mult = {{eMedicine2|ped|2569}} {{eMedicine2|oph|480}} | MeshID = D003877 }} {{Diseases of the skin and appendages by morphology}} {{Diseases of the skin and subcutaneous tissue}}
{{DEFAULTSORT:Contact Dermatitis}} Category:Contact dermatitis Category:Allergology Dermatitis, Occupational