Contact dermatitis can be caused by allergic reactions (allergic contact dermatitis) or irritants (irritant contact dermatitis). Allergic contact dermatitis is a type IV delayed hypersensitivity reaction that occurs when a sensitized individual is re-exposed to an allergen. It accounts for about 20% of contact dermatitis cases. Patch testing is needed to identify the specific allergen causing allergic contact dermatitis. Irritant contact dermatitis results from direct skin damage caused by chemicals, metals, fabrics, or other irritating substances. Avoiding the irritating or allergenic substance is the primary treatment approach for both types of contact dermatitis.
3. What Is Dermatitis ?
Dermatitis is the inflammation of the
skin caused by factors such as:
1.Allergies
2.Irritants
3.Ultraviolet light
4.Foods
5.Medications
6.Hereditary
4. Types of Dermatitis
⢠SEBORRHEIC DERMATITIS [Skin eruptions on face, scalp, and
trunk of body. This symptoms will produce greasy, dry scales
and will appear reddish.]
⢠CONTACT DERMATITIS [The appearance of skin vesicles that
burn, itch , sting or scale. ]
⢠ATOPIC DERMATITIS [There will appear lesions on the face,
neck, knees, elbows, trunk of body.]
5. SEBORRHEIC DERMATITIS
⢠affect the areas rich in sebaceous glands
⢠Fungal infection:
⢠Malassezia globosa ,
⢠Malassezia restricta
⢠Genetic,
⢠environmental,
⢠hormonal, and
immune-system factors
have been shown to be involved in the manifestation of seborrhoeic
dermatitis
7. ⢠ICD is a cutaneous inflammation resulting from a direct
cytotoxic effect of a chemical or physical agent
⢠Constitutes nearly 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
8. Contact dermatitis:
Definition:
Contact dermatitis is a term for a skin reaction (dermatitis)
resulting from
exposure to
â˘ALLERGENS (ALLERGIC CONTACT DERMATITIS)
OR
â˘IRRITANTS(IRRITANT CONTACT DERMATITIS).
â˘Phototoxic dermatitis occurs when the allergen or irritant is
activated by sunlight.
10. Irritant contact dermatitis:
It is a form of contact dermatitis that can be divided into forms caused
by chemical irritants and those caused by physical irritants.
14. Pathogenesis of ICD
⢠Denaturation of epidermal keratins
⢠Disruption of the permeability barrier
⢠Damage to cell membranes
⢠Direct cytotoxic effects
16. Cumulative Irritant Contact Dermatitis
⢠Consequence of multiple sub-
threshold skin insults, without
sufficient time between them for
complete barrier function repair
⢠In contrast to acute ICD, the lesions
of chronic ICD are less sharply
demarcated
⢠Itching and pain due to fissures of
hyperkeratotic skin are symptoms
of chronic ICD
⢠Skin findings include
lichenification, hyperkeratosis,
xerosis, erythema, and vesicles
17. Asteatotic Dermatitis
⢠Exsiccation eczematid ICD
⢠Seen mainly during the winter
months in elderly individuals
who frequently bath without
remoisturizing
⢠Skin appears dry with
ichthyosiform scale and
patches of eczema craquele
18. Traumatic Irritant Contact Dermatitis
⢠May develop after acute skin trauma, such as burns, lacerations, or
acute ICD
⢠Patients should be asked if they have cleansed with strong soaps or
detergents
⢠Characterized by eczematous lesions most commonly on the hands,
that persist
⢠Healing is delayed with redness, infiltration, scale, and fissuring in
the affected areas
19. Traumatic Irritant Contact Dermatitis
⢠Reports of stinging or burning in the absence of visible
cutaneous signs of irritation
⢠Response to irritants such as lactic or sorbic acid
20. Pustular and Acneform Irritant Contact Dermatitis
ďśResult to certain irritants such as
metals, croton oil, mineral oils, tars,
greases, cutting and metal working
fluids, and naphthalenes
ďśShould be considered in conditions
in which folliculitis or acneform
lesions develop in setting outside of
typical acne
ďśPustules are sterile and transient
ďśMilia may develop in response to
occlusive clothing, adhesive tape,
ultraviolet and infrared radiation
Chloracne. Note heavy involvement of retroauricular skin
with comedones and cysts
21. Airborne Irritant Contact Dermatitis
ďśDevelops on irritant-exposed skin
of the face and periorbital regions
ďśOften simulates photoallergic
reactions
ďśInvolvement of the upper eyelids,
philtrum, and submental regions
help to differentiate from
photoallergic reaction
22. Frictional Irritant Contact Dermatitis
ďśResults from repeated low-grade
frictional trauma
ďśPlays adjuvant role in ACD and ICD
ďśCharacterized by hyperkeratosis,
acanthosis, and lichenification,
often progressing to hardening,
thickening, and increased
toughness
9 year old girl demonstrates a lichenified hyperpigmented round plaque on
the top of her thumb produced by chronic thumbsucking.
www.dermatlas.org
23. Pathology of ICD
ďśVariable mix of inflammation, necrosis of epidermal keratinocytes, and mild
spongiosis
ďśCombination of an upper dermal perivascular infiltrate of lymphocytes with
minimal extension of inflammatory cells into the overlying epidermis, and
widely scattered necrotic keratinocytes is most typical picture
ďśTrue features of interface dermatitis are absent, and spongiosis should be
focal or absent
ďśOver time additional histologic findings include acanthosis with mild
hypergranulosis and hyperkeratosis
24. Acids
ďśInorganic and organic acids can be corrosive to the skin
ďśCause epidermal damage via protein denaturation and cytotoxicity
ďśSymptoms include erythema, vesication, and necrosis
ďśHydrofluoric and sulfuric acid can cause the most severe burns
ďśHydrofluoric acid, used in the semiconductor industry, is able to
penetrate intact skin with subsequent dissociation in deeper tissues
and resultant liquefactive necrosis
25. Acids
ďśChromic acid causes ulcerations
known as âchrome holesâ and often
perforates the nasal septum
ďśChemical burns and irritant
dermatitis from nitric acid can cause
a distinctive yellow discoloration
ďśIn general, organic acids are less
irritating than inorganic acids
ďśFormic acid has the greatest
corrosive potential of the organic
acids
Examples of chrome holes www.cdc.gov/niosh/ocderm
26. Alkalis
ďś Strong Alkalis include sodium, ammonium,
potassium hydroxide, sodium and
potassium carbonate, and calcium oxide
ďś Found in soaps, detergents, bleaches,
ammonia preparations, lye, drain pipe
cleaner, toilet bowl cleansers, and oven
cleaner
ďś Often more painful and damaging than
acids
ďś No vesicles, necrotic skin that appears dark
brown then black, ultimately becomes
hard, dry, and cracked
ďś Alkalis disrupt barrier lips and denature
proteins with subsequent fatty acid
saponification
27. Alkalis
ďśCement mixed with water can cause
ulcerative damage due to alkalinity
ďśChanges appear 8 to 12 hours after
exposure
ďśChronic irritant cement dermatitis
may also develop over months to
years
ďśCan accompany allergic contact
dermatitis
Hand dermatitis due to contact with cement
dermnetnz.org/dermatitis/chrome
28. Metal Salts
ďśInclude arsenic trioxide, beryllium compounds, calcium oxide,
copper salts, inorganic mercury, thimerosal, and selenium
ďśSigns ranging from ulceration to folliculitis
29. Solvents
ďśAct mainly by dissolving the intercellular lipid barrier of
the epidermis
ďśProlonged skin contact can result in severe burns and well
as systemic toxicity
ďśExamples include turpentine, benzene, toluene, xylene,
carbon tetrachloride, gasoline, and kerosene
30. ďŽProfessional paint and crayon illustrator with bilateral palmar dermatitis secondary to
repeated contact with paint solvents. Extensive patch testing excluded allergic contact
dermatitis
31. Detergents and Cleansers
ďśInclude any surface active agent (surfactant) that concentrates at the
oil-water interfaces and has both emulsifying and cleansing
properties
ďśFound in skin cleansers, cosmetics, and household cleaning products
ďśSurfactants cause protein denaturation of the stratum corneum,
impairing barrier function
ďśAnionic detergents such as alkyl sulfates and alkyl carboxylate salts
are the most irritating
32. Disinfectants
⢠Include, alcohols, aldehydes,
phenolic compounds, halogenated
compounds, surfactants, dyes,
oxidizing agents, and mercury
compounds
⢠Weak toxic agents that can cause
chronic ICD
Practicing dentist with moderately severe irritant hand dermatitis from chronic exposure to
disinfecting solutions and antiseptics. The results of patch testing, latex challenge testing, and RAST
testing were negative.
33. Plastics
ďśThree categories: thermoplastics, thermosettings,
elastomers
ďśSkin damage is attributed to monomer ingredients,
hardeners, and stabilizers
ďśFinal hardened plastic product is generally considered
inert
34. Food
ďśAgriculture, fishing, catering, and food
processing
ďśOften work without gloves, in damp
working conditions with frequent hand
washing
ďśMechanical, thermal, and climatic factors
ďśNearly 100% of exposed persons in food
handling and fishing professions may be
affected by chronic irritant hand
dermatitis
35. Water
ďśUbiquitous skin irritant
ďśTropical immersion foot, seen
during Vietnam War
ďśHairdressers, hospital cleaners,
cannery workers, bartenders
ďśIrritancy 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 washes over 10 times a day.
36. Fabric/man-made vitreous fibers
ďśFibers larger than 3.5 um in
diameter cause the highly pruritic
contact dermatitis caused by
fiberglass
ďśErythematous papules with
superimposed excoriations on neck
and dorsal hands
ďśWool and rough clothing cause
dermatitis in atopic individuals
Fiberglass dermatitis www.cdc.gov/niosh/ocderm
37. Differential Diagnosis
ďśAllergic and ICD, especially in chronic stage appear similar
by clinical appearance, histology, and immunohistology
ďśLook identical with erythema, papules, xerosis, scaling,
and lichenification with sharp borders
ďśICD has remained a diagnosis of exclusion when dermatitis
is not explained by positive patch test to a known allergen
ďśMore frequent complaint of burning and stinging with ICD
in contrast to pruritus in ACD
38. Treatment
ďśAvoidance of causative irritants at home or in the workplace is the primary TX
ďśEngineering controls to reduce exposure in the workplace
ďśShielding and personal protection such as gloves and special clothing
ďśPre-exposure protection by protective creams, removal of irritants by mild cleaning agents,
and enhancement of barrier function generation by emollients and moisturizers
ďśEmphasizing personal and occupational hygiene
ďśEstablishing educational programs to increase awareness in the workplace
39. Allergic contact dermatitis (ACD)
⢠ACD accounts for approximately 20% of all
contact dermatitis
⢠ACD 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 sensitized
⢠Synonyms include contact dermatitis and
contact eczema
Allergic contact dermatitis. Linear streaks seen with ACD to poison ivy.
40. Acute Contact Dermatitis
⢠Key Features
ďśACD is a pruritic, eczematous reaction
ďśAcute ACD and many cases of chronic
ACD are well demarcated and located to
the site of contact with the allergen
ďśPrototypic reactions are ACD due to
poison ivy and nickel
ďśPatch testing remains the gold standard
for accurate and consistent diagnosis
This healthy adolescent developed an intensely pruritic
vesiculobullous allergic contact dermatitis from hair dye.
41. ďśClassic picture of ACD is a well-demarcated
erythematous vesicular and/or scaly patch or
plaque with well defined margins
corresponding to the area of contact
ď 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.
42. ⢠Allergic contact dermatitis to
leather shoes. Note the
correspondence to sites of exposure.
Courtesy of Yale Residents Slide Collection.
43. ďśBecause ICD and ACD are not
always differentiable clinically,
patch testing is required to help
identify an allergen or exclude an
allergy to a suspected allergen.
ď Allergic contact dermatitis. Chronic hand dermatitis due to ACD to mercaptobenzothiazole found
in rubber gloves
44. Epidemiology of ACD
ďśAffects the old and young, individuals of all races, and both sexes
ďśDifferences in genders usually based on exposure patterns, such as nickel
allergy being seen more frequently in women, presumably due to greater
exposure to jewelry
ďśOccupations and avocations play an important role
ďśAllergens differ from region to region, e.g. preservatives used in personal care
products can vary based on government legislation
45. Pathogenesis of ACD
ďśACD is a type IV hypersensitivity response
ďśRequires prior sensitization to the chemical in question
ďśSubsequent re-exposure of individual leads to allergen being presented to a
primed T-cell milieu leading to release of numerous cytokines and
chemotactic factors leading to the clinical picture of eczema
ďśOnce sensitized a low concentration of causative chemical elicits a response
46. ⢠Elicitation of contact hypersensitivity. Application of contact allergens (Ag) into a sensitized
individual causes the release of cytokines by keratinocytes and Langerhans cells. These
cytokines induce the expression of adhesion molecules and activation of endothelial cells
which ultimately attracts leukocytes to the site of antigen application. Among these cells, T
effector cells are present which are now activated upon antigen presentation either by
resident cells or by infiltrating Langerhans cells. Antigen-specific T cell activation again
induces the release of cytokines by T cells. This causes the attraction of other inflammatory
cells including granulocytes and macrophages which ultimately cause the clinical
manifestation of contact dermatitis. Ag, antigen; DDC, dermal dendritic cell; KC, keratinocyte;
CLA, cutaneous lymphocyte antigen.
47. Clinical features of ACD
⢠Acute blistering and weeping
⢠Chronic lichenified and scaly
plaques
⢠Patchy and diffuse distributions
may be seen with body washes and
shampoos
ď Acute bullous allergic
contact dermatitis due to
poison ivy. This
distribution is seen in
patients who wear gloves.
Courtesy of Yale Residents
Slide Collection
ď Chronic allergic contact dermatitis
due to glutaraldehyde. The patient was
an optometrist
48. Pathology of ACD
⢠ACD is the prototype of spongiotic dermatitis
⢠Acute stage: variable degree of spongiosis with mixed dermal
inflammatory infiltrate containing lymphocytes, histiocytes, and
variable numbers of eosinophils
⢠Moderate to severe reactions show intraepidermal vesiculation
⢠Subacute to chronic stages have epidermal hyperplasia, often
psoriasiform
49. Treatment of ACD
⢠Involves identification of causative allergens
⢠Clear the dermatitis with topical, or if necessary systemic
corticosteroids
⢠Complete and prolonged clearing can take up to 6 weeks or
more, even when allergens are being avoided
50.
51. Nickel
⢠Most common allergen tested by the
NACDG, with 14% of patients
reacting to it
⢠Relevance has been estimated to be
50%
⢠Commonly used in jewelry, buckles,
snaps, and other metal-containing
objects
⢠High rate of sensitivity attributed to
ear piercing
⢠Dimethylglyoxime test to determine
if a particular item contains nickel
⢠Individuals with nickel allergy
should avoid custom jewelry, and
can usually wear stainless steel or
52. Neomycin Sulfate
⢠Most commonly used topical antibiotic
⢠Most common sensitizer among topical
antibiotics
⢠Found in many OTC preparations: bacterial
ointments, hemorrhoid creams, and otic and
opthalmic preparations
⢠Frequently used with other antibacterial agents,
such as bacitracin and polymyxin, as well as
corticosteroids
⢠Co-reactivity is commonly seen with neomycin
and bacitracin
13 year old boy developed an itchy allergic contact dermatitis from a topical antibiotic.
www.dermatlas.org
53. Balsam of Peru
⢠Naturally occurring fragrance material
⢠Prior to introduction of fragrance mix in the 1970âs, balsam of Peru was used to
screen for fragrance allergy
⢠Capable of identifying 50% of those allergic to fragrance
⢠Seen in those with allergies to spices, in particular cloves, Jamaicin pepper, and
cinnamon
⢠Patients with a positive reaction need to avoid fragrances, occasionally spices,
and other sources such as colas, tobacco, wines, and vermouth
54. Thimerosal
⢠Thimerosal is a combination of thiosalicylic acid and ethylmercuric
chloride, and is used as a preservative
⢠Most sensitization may be due to its use as a preservative in
vaccines
⢠Other exposures include: contact lens solution, otic and opthalmic
solutions, antiseptics, and cosmetics
⢠Positive reactions are common, relevance is low and therefore
routine testing to this allergen should be reconsidered
55. Gold
⢠Gold allergy is found a positive rate of 9.5%
⢠NACDC found 90% of gold-allergic patients were women, and there was a
higher rate of nickel (33.5%) and cobalt allergy (18%) in this group
⢠Most common clinical picture is hand, facial, or eyelid dermatitis
⢠Systemic reactions to gold in patients whom it was used to tx RA, SLE, or
pemphigus.
⢠Cutaneous findings of lichen planus-like reactions to pityriasis rosea-like
reactions and papular eruptions with systemic reactions
56. Formaldehyde
⢠Is a ubiquitous, colorless gas found in the workplace, cosmetics, medications, textiles, paints,
cigarette smoke, paper, and formaldehyde resins in plastic bottles
⢠Commonly seen in association with formaldehyde-releasing presevatives, such as
quarternuim-15 imidazolidinyl urea, diazolidinyl urea, DMDM hydantoin, 2-bromo-2-
nitropropane-1-3,diol, and tris(hydroxymethyl)nitromethane
⢠ICD is most common, ACD, contact urticaria, and mucous membrane irritation can occur
⢠Textile dermatitis due to formaldehyde resins in âwash-and-wearâ and wrinkle resistant
clothes
⢠Another source of formaldehyde is âformaldehyde-freeâ products that are packaged in
containers coated with formaldehyde resins
⢠So widespread that avoidance is difficult and clinical relevance should be determined
57. Quaternium-15
⢠Preservative that is an effective biocide
against Pseudomonas, as well as other
bacteria and fungi
⢠Most common preservative to cause ACD
⢠Found in shampoos, moisturizers,
conditioners, and soaps
⢠80% of those reacting to quarternium-15
are also formaldehyde sensitive
Hand dermatititis due to
quaternium-15 in a moisturiser
dermnetnz.org/dermatitis/quaternium
58. Cobalt
⢠Metal that is used in association with other
metals to add hardness and strength
⢠Frequently combined with nickel, chromium,
molybdenum, and tungsten
⢠80% of individuals with a cobalt sensitivity
have a co-sensitivity to chromate (more
common in men) or nickel (more common in
women)
⢠Exposure through jewelry snaps, buttons, tools,
cosmetics, hair dyes, joint replacements,
ceramics, enamel, cement, paints , and resins
59. Bacitracin
⢠Topical antibiotic with activity
against Gram-positive bacteria and
spirochetes
⢠Commonly used in combination
with other antibiotics such as
neomycin and with corticosteroids
⢠In addition to ACD, also rarely
causes anaphylaxis and contact
urticaria
Chronic ulcerations on the lower extremity are particularly likely to
develop allergic contact dermatitis. This eruption resulted from
sensitization to bacitracin. www.worldallergy.org
60. Systemic Contact Dermatitis
⢠Systemic exposure to a chemical may
result in a diffuse dermatitis
⢠Patient has had a prior contact
allergy and then becomes exposed
through a systemic route, such as
injection, oral, intravenous, or
intranasal administration
⢠One of most common examples is
patient with ethylenediamine allergy
and subsequent reaction to
aminophylline
61.
62. 55-year-old farm worker developed a chronic allergic contact
dermatitis to airborn allergens (compositae).
63. Patch test:
1. A patch test relies on the principle of a type IV hypersensitivity reaction.
2. When the skin is exposed to an allergen, the antigen presenting cells (APCs) -
also known as Langerhans cell or Dermal Dendritic Cell - eat up substance
(phagocytoze) and break it into smaller pieces. his is where a substance is
recognized by immune cells in the skin.
3. They then put parts of the substance onto their surface (technically holds the
part of the molecule on the surface in the major histocompatibility complex type
two (MHC-II).
4. Once this is done the APC moves down the lymphatic system to a lymph node
where it presents this part of the substance (what we now call an antigen) to a
particular immune cell called a CD4+ T-cell or T-helper cell.
64. 5.The T-cell, if it recognizes the substance as dangerous, expands in number
and sends out more of itself to the skin, at the site of antigen exposure.
6. When the skin is again exposed to the antigen, the memory t-cells in the
skin recognize the antigen and produce cytokines (chemical signals)
which cause more T-cells to migrate from blood vessels. This starts a
complex immune cascade leading to skin inflammation, itching and the
typical rash of contact dermatitis.
7.In general, it takes 2 to 4 days for a response in patch testing to develop. The
patch test is really just induction of a contact dermatitis in a small area
Interestingly, the size of the molecule necessary to be picked up and
recognized is ten times the size of the largest molecule that can pass
through the skin. Therefore, it is likely that an antigen (like nickel) when it
has passed through the skin, combines with something else before it is
recognized.