Allergic contact dermatitis (ACD) is a common inflammatory skin disease resulting from direct or indirect contact with allergens, primarily affecting those with prior sensitization. The prevalence varies significantly between populations, with diagnoses often confirmed through patch testing and careful clinical evaluation. Treatment involves allergen avoidance, topical corticosteroids, and potentially systemic corticosteroids for severe cases.

1. Allergiccontactdermatitis
SHIKHAR
GROUP- III

2. Outline
⚫ Epidemiology
⚫ Pathophysiology
⚫ Clinical evaluation
⚫ Treatment

3. Introduction
⚫ Occurs after direct or indirect contact with
substances
⚫ Major cause of occupational skin disease
⚫ Common inflammatory skin disease

4. Classification
⚫ Allergic contact dermatitis
⚫ Inflammation caused by allergen specific
T lymphocytes
⚫ Prior sensitization necessary

5. Epidemiology
⚫ In USA
⚫ Cohort overall prevalence 24,400 /100,000
people
⚫ population-based studies in Europe
⚫ Prevalence 0.7% - 18.6% for ACD
⚫ Incidence of OCD in other countries 1.3 - 19
cases per 10,000

6. Histology
⚫ Epidermal changes of
spongiosis
⚫ Dense lymphocytic
infiltrate in upper
dermis
⚫ Epidermal exocytosis of
lymphocytes

7. PATHOPHYSIOLOGY AND
CLINICAL EVALUATION
⚫ ACD
⚫ Prototype of
type IV cell-
mediated
hypersensitivit
y reaction
 Diagnosis of ACD
suspected from clinical
presentation and possible
exposure to contact
allergen

10. Clinical presentations
⚫ Allergic contact dermatitis

11. Investigation : Patch testing 1
⚫ Indicated in patients with chronic, pruritic eczematous or
lichenified dermatitis in whom ACD is suspected
⚫ Affected by
⚫ Oral corticosteroid [>20 mg of prednisolone/day or
equivalent]
⚫ Cancer chemotherapy or immunosuppressive drug
⚫ Topical corticosteroid should be discontinued for 5-7 days
before patch testing
⚫ Not affected by antihistamines

12. Investigation : Patch testing 2
⚫ Sources of allergens
T.R.U.E. TEST : Not US FDA approved but
recommended by CD experts

13. Investigation : Patch testing 3
⚫ Numbers of allergens
⚫ Ideal number remains controversial
⚫ T.R.U.E. Test contains 29 allergens
⚫ Higher false-negative reactions to neomycin,
thiuram mix, balsam of Peru, fragrance mix,
cobalt and lanolin
⚫ NACDG series range from 65-70 allergens
⚫ T.R.U.E test serve as screening tool in
allergist practice

15. Patch test technique
⚫ Applied to upper or middle back areas (2.5 cm lateral to
midspinal reference point) free of dermatitis and hair
⚫ Kept in place for 48 hours
⚫ Read 30 minutes after removal of patches
⚫ Second reading should be done 3 to 5 days after initial
application
⚫ Metals , topical antibiotics , topical orticosteroids, and PPD can
elicit positive reactions after 7 days
⚫ Nonstandardized patch tests tested at 1:10 to 1:100
dilutions

16. Patch test technique

21. Investigation : ROAT
⚫ Improving reliability of interpreting tests for
leave-on products
⚫ Suspected allergens are applied to antecubital fossa
twice daily for 7 days and observed for dermatitis
⚫ Absence of reaction makes CD unlikely
⚫ If eyelid dermatitis is considered
⚫ ROAT can be performed on back of ear

22. Occupational contact dermatitis
⚫ 4 of 7 criteria must be positive to conclude OCD
⚫ Clinical appearance consistent with CD
⚫ Cutaneous irritants or allergens present in workplace
⚫ Anatomic distribution of dermatitis consistent with skin exposure to
chemicals in course of various job tasks
⚫ Temporal relationship between exposure and onset of symptoms
consistent with CD
⚫ Nonoccupational exposures excluded as probable causes of dermatitis
⚫ Dermatitis improves away from work exposure and reexposure causes
exacerbation
⚫ There are positive-reaction and relevant patch tests performed
according to established guidelines

23. Selected contact dermatitis : Metals 1
Nickel
⚫ 18.7% positive patch test reaction to
nickel
⚫ Female sensitization to nickel higher
⚫ 1% of nickel allergy have systemic
reactions to nickel content of normal diet

24. Luz S. Fonacier et al J Allergy Clin Immunol 2010;125:138-49

26. www.

28. Selected contact dermatitis : Metals 2
Gold
⚫ NACDG reported that 389/4101(9.5%)
positive patch test reactions to gold
⚫ Hands (29.6%), face with seborrheic
distribution (19.3%) and eyelids (7.5%)
⚫ Used for fashion appeal, anti-inflammatory
medication, used in electroplating industry,
part of dental appliances

29. Selected contact dermatitis : Cosmetics 1
Fragrance
⚫ Most common cause of ACD from cosmetics
⚫ Positive patch test reactions in 10.4% of patients
⚫ ‘‘Unscented’’ and ‘‘Fragrance-free’’
⚫ Fragrance mix I contains allergens found 15%-100%
of cosmetic products and might detect ~85% of
subjects with fragrance allergy

30. Selected contact dermatitis : Cosmetics 2
Preservatives and excipients
⚫ Lanolin
⚫ Common component of consumer
products
⚫ Weak sensitizer on normal skin but stronger
sensitizer on damaged skin
⚫ Stasis dermatitis, higher risk of lanolin
sensitivity

31. Selected contact dermatitis : Cosmetics 3
Preservatives and excipients
⚫ Cosmetic preservatives
⚫ Formaldehyde releasers
⚫ Non–formaldehyde releasers : Paraben

33. Selected contact dermatitis : Cosmetics 4
Hair products
⚫ PPD (Paraphenylenediamine)
⚫ Most common cause of CD in
hairdressers
⚫ PPD cross-reacts with COX-2 inhibitor
(celecoxib), sunscreens, and antioxidants
used in manufacture of rubber products

34. Selected contact dermatitis :
Cosmetics 5
Hair products
⚫ CAPB ( Cocoamidopropyl betaine )
⚫ Amphoteric surfactant often found in
shampoos, bath products, and eye and
facial cleaners

35. Selected contact dermatitis : Cosmetics 6
Hair products
⚫ Glycerol thioglycolate
⚫ Active ingredient in permanent wave
solution
⚫ Might remain allergenic in hair long
after rinsed out

36. Medications 1
Antibiotics and antiseptics
⚫ Neomycin and nitrofurazone potent
sensitizers
⚫ Neomycin sulfate cross-sensitize with
gentamicin, kanamycin, streptomycin,
spectinomycin, tobramycin and
paromomycin

37. Medications 2
Corticosteroid
⚫ Patients with worsening of previous dermatitis or initial
improvement followed by deterioration of dermatitis after
application of corticosteroids should be evaluated for
corticosteroid allergy
⚫ Cross-reactivity between groups A and D2 and groups B
and D2 has been reported
⚫ 30% of ACD to corticosteroids be missed if delayed 7-
day reading not done

39. Surgical implant devices 1
⚫ Use of nickel in biomedical devices,led to
increasing concern about safety in
suspected nickel-sensitized patients
⚫ No large, evidence-based guidelines

40. Surgical implant devices 2
⚫ Criteria for diagnosis of cutaneous implant–induced
reaction
⚫ Dermatitis (localized/generalized) appearing after
implant surgery
⚫ Persistent dermatitis (resistant to appropriate
therapies)
⚫ Positive patch test (history to metallic component of
implant or to commonly used acrylic glues)
⚫ Resolution of dermatitis after removal of implant

41. Treatment 1
⚫ Allergen identification to improve contact avoidance
⚫ Alternatives and substitutes to cosmetics should be offered
to patient to increase compliance
⚫ Supportive care and relief of pruritus
⚫ Excessive handwashing and nonirritating or sensitizing
moisturizers must be used after washing

42. Treatment 2
⚫ TC is first-line treatment for ACD
⚫ Extensive(>20% BSA) and severe CD,
systemic corticosteroids might offer faster
relief (12-24hr)
⚫ Recommended dose is 0.5 to 1 mg/kg daily for
5 to 7 days, and only if patient is comfortable
at that time is dose reduced by 50% for next 5
to 7 days Luz S. Fonacier et al J Allergy Clin Immunol 2010;125:138-49
Vincent S. Beltrani et al Annals of Allergy, Asthma and Immunology 2006;97:1-30

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