1、Contact Dermatitis Part One,Boris Ioffe, D.O., Pharm.D. 08-14-06,Irritant contact dermatitis (ICD),Accounts for approximately 80% of all contact dermatitisICD is the result of a local toxic effect when the skin comes in contact with irritant chemicals such as soaps, solvents, acids, or alkalis,This
2、37-year-old woman developed a contact irritant dermatitis from obsessive-compulsive hand washing 20-30 times a day. www.drmatlas.org,Introduction to Irritant Contact Dermatitis,ICD is a cutaneous inflammation resulting from a direct cytotoxic effect of a chemical or physical agent Constitutes nearly
3、 80% of occupational contact dermatitis (OCD) OCD is a matter of public health importance, contributing to combined direct and indirect annual costs (in the USA) of up to $1 billion when accounting for medical costs, workers compensation, and lost time from work,Epidemiology of ICD,The US Bureau of
4、Labor Statistics data show that occupational skin diseases accounted for 10% to 15% of all occupational illnessesHigh-risk occupations with frequent irritant exposure in caterers, furniture industry workers, hospital workers, hairdressers, chemical industry workers, dry cleaners, metal workers, flor
5、ists, and warehouse workers,Epidemiology of ICD,Clinical manifestations of ICD are determined by:Properties of the irritating substanceHost factorsEnvironmental factors including concentration, mechanical pressure, temperature, humidity, pH, and duration of contactCold alone may also reduce the plas
6、ticity of the horny layer, with consequent cracking of the stratum corneumOcclusion, excessive humidity, and maceration increase percutaneous absorption of water-soluble substances,Bilateral shoe irritant dermatitis resulting from chronic occlusive footwear,Epidemiology of ICD,Important predisposing
7、 characteristics of the individual include: Age, race, sex, pre-existing skin disease, anatomic region exposed, and sebaceous activityBoth infants and elderly are affected more by ICD because of their less robust epidermal layerPatients with darkly pigmented skin seem to be more resistant to irritan
8、t reactions Other skin disease such as active atopic dermatitis may predispose an individual to develop ICDThe most commonly affected sites are exposed areas such as the hands and the face, with hand involvement in approximately 80% of patients and face involvement in 10%,Pathogenesis of ICD,Denatur
9、ation of epidermal keratinsDisruption of the permeability barrierDamage to cell membranesDirect cytotoxic effects,Acute Irritant Contact Dermatitis,Commonly seen in occupational accidents Irritant reaction reaches its peak quickly, within minutes to hours after exposure Symptoms include stinging, bu
10、rning, and soreness Physical signs include erythema, edema, bullae, and possibly necrosis Lesions restricted to the area where the irritant or toxicant damaged the tissue Sharply demarcated borders and asymmetry pointing to an exogenous cause Most frequent irritants are acids and alkaline solutions,
11、Acute Delayed Irritant Contact Dermatitis,Delayed inflammatory response characteristic of certain irritants such as anthralin, benzalkonium chloride, and ethylene oxideVisible inflammation is not seen until 8 to 24 hours after exposureSymptoms are more frequently burning rather than pruritusSensitiv
12、ity to touch and water are elicitedThis form of ICD is commonly seen during diagnostic patch testing,Irritant Reaction Irritant Contact Dermatitis,Type of subclinical irritant dermatitis in individuals exposed to wet chemical environments such as hairdressers, caters, or metalworkersCharacterized by
13、 scaling, redness, vesicles, pustules, and erosionsOften begins under occlusive jewelry and then spreads over the fingers to the hands and forearmsMay simulate dyshidrotic dermatitis,Cumulative Irritant Contact Dermatitis,Consequence of multiple sub-threshold skin insults, without sufficient time be
14、tween them for complete barrier function repairIn contrast to acute ICD, the lesions of chronic ICD are less sharply demarcatedItching and pain due to fissures of hyperkeratotic skin are symptoms of chronic ICDSkin findings include lichenification, hyperkeratosis, xerosis, erythema, and vesicles,Ast
15、eatotic Dermatitis,Exsiccation eczematid ICDSeen mainly during the winter months in elderly individuals who frequently bath without remoisturizingSkin appears dry with ichthyosiform scale and patches of eczema craquele,Traumatic Irritant Contact Dermatitis,May develop after acute skin trauma, such a
16、s burns, lacerations, or acute ICDPatients should be asked if they have cleansed with strong soaps or detergentsCharacterized by eczematous lesions most commonly on the hands, that persist Healing is delayed with redness, infiltration, scale, and fissuring in the affected areas,Pustular and Acneform
17、 Irritant Contact Dermatitis,Result to certain irritants such as metals, croton oil, mineral oils, tars, greases, cutting and metal working fluids, and naphthalenesShould be considered in conditions in which folliculitis or acneform lesions develop in setting outside of typical acnePustules are ster
18、ile and transientMilia may develop in response to occlusive clothing, adhesive tape, ultraviolet and infrared radiation,Chloracne. Note heavy involvement of retroauricular skin with comedones and cysts,Subjective or Sensory Irritant Contact Dermatitis,Reports of stinging or burning in the absence of
19、 visible cutaneous signs of irritationResponse to irritants such as lactic or sorbic acid,Airborne Irritant Contact Dermatitis,Develops on irritant-exposed skin of the face and periorbital regionsOften simulates photoallergic reactionsInvolvement of the upper eyelids, philtrum, and submental regions
20、 help to differentiate from photoallergic reaction,Frictional Irritant Contact Dermatitis,Results from repeated low-grade frictional traumaPlays adjuvant role in ACD and ICDCharacterized by hyperkeratosis, acanthosis, and lichenification, often progressing to hardening, thickening, and increased tou
21、ghness,9 year old girl demonstrates a lichenified hyperpigmented round plaque on the top of her thumb produced by chronic thumbsucking. www.dermatlas.org,Pathology of ICD,Variable mix of inflammation, necrosis of epidermal keratinocytes, and mild spongiosisCombination of an upper dermal perivascular
22、 infiltrate of lymphocytes with minimal extension of inflammatory cells into the overlying epidermis, and widely scattered necrotic keratinocytes is most typical pictureTrue features of interface dermatitis are absent, and spongiosis should be focal or absent Over time additional histologic findings
23、 include acanthosis with mild hypergranulosis and hyperkeratosis,Acids,Inorganic and organic acids can be corrosive to the skinCause epidermal damage via protein denaturation and cytotoxicitySymptoms include erythema, vesication, and necrosisHydrofluoric and sulfuric acid can cause the most severe b
24、urnsHydrofluoric acid, used in the semiconductor industry, is able to penetrate intact skin with subsequent dissociation in deeper tissues and resultant liquefactive necrosis,Acids,Chromic acid causes ulcerations known as chrome holes and often perforates the nasal septumChemical burns and irritant
25、dermatitis from nitric acid can cause a distinctive yellow discoloration In general, organic acids are less irritating than inorganic acidsFormic acid has the greatest corrosive potential of the organic acids,Examples of chrome holes www.cdc.gov/niosh/ocderm,Alkalis,Strong Alkalis include sodium, am
26、monium, potassium hydroxide, sodium and potassium carbonate, and calcium oxideFound in soaps, detergents, bleaches, ammonia preparations, lye, drain pipe cleaner, toilet bowl cleansers, and oven cleanerOften more painful and damaging than acidsNo vesicles, necrotic skin that appears dark brown then
27、black, ultimately becomes hard, dry, and crackedAlkalis disrupt barrier lips and denature proteins with subsequent fatty acid saponification,Alkalis,Cement mixed with water can cause ulcerative damage due to alkalinityChanges appear 8 to 12 hours after exposureChronic irritant cement dermatitis may
28、also develop over months to yearsCan accompany allergic contact dermatitis,Hand dermatitis due to contact with cement dermnetnz.org/dermatitis/chrome,Metal Salts,Include arsenic trioxide, beryllium compounds, calcium oxide, copper salts, inorganic mercury, thimerosal, and seleniumSigns ranging from
29、ulceration to folliculitis,Solvents,Act mainly by dissolving the intercellular lipid barrier of the epidermisProlonged skin contact can result in severe burns and well as systemic toxicityExamples include turpentine, benzene, toluene, xylene, carbon tetrachloride, gasoline, and kerosene,Professional
30、 paint and crayon illustrator with bilateral palmar dermatitis secondary to repeated contact with paint solvents. Extensive patch testing excluded allergic contact dermatitis,Detergents and Cleansers,Include any surface active agent (surfactant) that concentrates at the oil-water interfaces and has
31、both emulsifying and cleansing propertiesFound in skin cleansers, cosmetics, and household cleaning productsSurfactants cause protein denaturation of the stratum corneum, impairing barrier functionAnionic detergents such as alkyl sulfates and alkyl carboxylate salts are the most irritating,Disinfect
32、ants,Include, alcohols, aldehydes, phenolic compounds, halogenated compounds, surfactants, dyes, oxidizing agents, and mercury compoundsWeak toxic agents that can cause chronic ICD,Practicing dentist with moderately severe irritant hand dermatitis from chronic exposure to disinfecting solutions and
33、antiseptics. The results of patch testing, latex challenge testing, and RAST testing were negative.,Plastics,Three categories: thermoplastics, thermosettings, elastomersSkin damage is attributed to monomer ingredients, hardeners, and stabilizersFinal hardened plastic product is generally considered
34、inert,Food,Agriculture, fishing, catering, and food processingOften work without gloves, in damp working conditions with frequent hand washingMechanical, thermal, and climatic factorsNearly 100% of exposed persons in food handling and fishing professions may be affected by chronic irritant hand derm
35、atitis,Water,Ubiquitous skin irritantTropical immersion foot, seen during Vietnam WarHairdressers, hospital cleaners, cannery workers, bartendersIrritancy of water is exacerbated by occlusion,9 year old is an habitual hand washer who develops a contact irritant dermatitis every winter. At times she
36、washes over 10 times a day. www.dermatlas.org,Fabric/man-made vitreous fibers,Fibers larger than 3.5 um in diameter cause the highly pruritic contact dermatitis caused by fiberglassErythematous papules with superimposed excoriations on neck and dorsal handsWool and rough clothing cause dermatitis in
37、 atopic individuals,Fiberglass dermatitis www.cdc.gov/niosh/ocderm,Differential Diagnosis,Allergic and ICD, especially in chronic stage appear similar by clinical appearance, histology, and immunohistologyLook identical with erythema, papules, xerosis, scaling, and lichenification with sharp borders
38、ICD has remained a diagnosis of exclusion when dermatitis is not explained by positive patch test to a known allergenMore frequent complaint of burning and stinging with ICD in contrast to pruritus in ACD,Treatment,Avoidance of causative irritants at home or in the workplace is the primary TXEnginee
39、ring controls to reduce exposure in the workplaceShielding and personal protection such as gloves and special clothingPre-exposure protection by protective creams, removal of irritants by mild cleaning agents, and enhancement of barrier function generation by emollients and moisturizersEmphasizing p
40、ersonal and occupational hygieneEstablishing educational programs to increase awareness in the workplace,TX Chemical Burns,Initial tx irrigation with large volumes of water, if chemical is insoluble in water a soap solution may be usedHigh pressure water to be avoided to prevent splashing2.5% calciu
41、m gluconate gel used to tx hydroflouric acid burns, immediate application of a weak acid such as vinegar, lemon juice, or 0.5% hydrochloric acid will lessen the effect of alkali burnsUlcerated areas should be managed with antibacterial creams or ointments to prevent secondary infectionFrequent evalu
42、ation is required because ulcers may progress over several daysExcision, debridement and/or grafting may speed healingMonitoring of blood, liver, and kidney function may be needed when exposed to chemicals with potential for systemic toxicity such as hydrofluoric acid, phenolic compounds, chromic ac
43、id, and gasoline,Chronic ICD Treatment,Tx goal is to restore normal epidermal barrier functionTopical corticosteroids frequently usedSystemic corticosteroids although helpful in reducing inflammation, are not useful in treatment of chronic ICD unless offending contactants are avoidedPUVA and Grenz r
44、ay considered for chronic dermatitis that does not respond to other txHyperkeratotic palmoplantar dermatitis from frictional or chronic ICD may benefit from the adjunctive use of systemic retinoids such as acitretin,Allergic contact dermatitis (ACD),ACD accounts for approximately 20% of all contact
45、dermatitisACD is a type IV, delayed or cell-mediated immune reaction that is elicited when the skin comes in contact with a chemical to which an individual has been previously sensitizedSynonyms include contact dermatitis and contact eczema,Allergic contact dermatitis. Linear streaks seen with ACD t
46、o poison ivy.,ACD,Key FeaturesACD is a pruritic, eczematous reactionAcute ACD and many cases of chronic ACD are well demarcated and located to the site of contact with the allergenPrototypic reactions are ACD due to poison ivy and nickelPatch testing remains the gold standard for accurate and consis
47、tent diagnosis,This healthy adolescent developed an intensely pruritic vesiculobullous allergic contact dermatitis from hair dye. Dermatlas.org,Classic picture of ACD is a well-demarcated erythematous vesicular and/or scaly patch or plaque with well defined margins corresponding to the area of conta
48、ct,Chronic allergic contact dermatitis leading to hand dermatitis. This golfer wore one leather glove and had positive patch tests to potassium dichromate and a piece of his glove. Courtesy of Kalman Watsky, M.D.,Allergic contact dermatitis to leather shoes. Note the correspondence to sites of expos
49、ure. Courtesy of Yale Residents Slide Collection.,Because ICD and ACD are not always discernable clinically, patch testing is required to help identify an allergen or exclude an allergy to a suspected allergen.,Allergic contact dermatitis. Chronic hand dermatitis due to ACD to mercaptobenzothiazole
50、found in rubber gloves,Epidemiology of ACD,Affects the old and young, individuals of all races, and both sexesDifferences in genders usually based on exposure patterns, such as nickel allergy being seen more frequently in women, presumably due to greater exposure to jewelryOccupations and avocations play an important roleAllergens differ from region to region, e.g. preservatives used in personal care products can vary based on government legislation,
