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Patch Test By H.Eshaghi M.D. Patch Test By H.Eshaghi M.D.

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Presentation on theme: "Patch Test By H.Eshaghi M.D. Patch Test By H.Eshaghi M.D."— Presentation transcript:


2 Patch Test By H.Eshaghi M.D

Non-immunologic inflammatory reaction of the skin due to an external agent Varied morphology Clinical types Chemical burns Irritant reactions Acute irritant contact dermatitis Chronic irritant contact dermatitis

4 Irritant Contact dermatitis :
Acute irritant dermatitis → severe eczematous reaction Single overwhelming exposure Few brief exposures to strong irritants or a caustic agent Chronic (cumulative) irritant dermatitis → eczematous changes that develop upon repeated exposure to weaker irritants: water, soaps, detergents, solvents, weak acids or alkalis, low humidity, heat, air, and dusts

5 Allergic Contact Dermatitis
Delayed type IV hypersensitivity reaction SENSITIZER: chemical agent with low molecular weight which is able to sensitize certain individuals and induce cell mediated immune reaction that end with dermatitis only in previously sensitized persons. Pathogenesis: Induction (sensitization) phase: days Elicitation phase: 2-4 days Antigen binds Langerhan’s cells in the epidermis or macrophages in the dermis Interaction with CD4+ T lymphyocytes at the regional lymph nodes causes release of inflammatory cytokines

6 Mechanism Specific immune phenomenon that is the result of a T cell mediated immune response to a defined allergen resulting in eczema or the exacerbation of a pre-existing dermatitis

7 Common allergens Chromate Rubber chemicals Preservatives Nickel
Fragrances Epoxy resins Phenol-formaldehyde resins

8 Contact dermatitis of the hands in a dental technician
Patch testing to be allergic to the Thiuram chemicals (accelerator in gloves)

9 Theoretical basis of patch testing
Patch test was first devised by Jadassohn(1895) and described in practical detail by Bloch (1929) immunological basis of the patch test is the type IV.

10 Hypersensitive Reactions
1. Type I Hypersensitivity 2. Type II Hypersensitivity 3. Type III Hypersensitivity 4. Type IV Hypersensitivity

11 Components and cells in Type I hypersensitivity
Allergen : pollen、dust mite、insects, etc selectively activate CD4+Th2 cells and B cells Allergen(IgE)and its production IgE: mainly produced by mucosal B cells in the lamina prapria special affinity to the same cell IL-4 is essential to switch B cells to IgE production High affinity receptor of the IgE on mast cell and basophil

12 Type I hypersensitivity

13 Type I hypersensitivity

14 Common disease of type I hypersensitivity
Systemic anaphylaxis: 1) Anaphylactic drug allergy :penicillin 2) Anaphylactic serum allergy : Respiratory allergic diseases : 1) Allergic asthma 2) Allergic rhinitis Gastrointestinal allergic diseases : The lack of Serum IgA protein hydrolase Undigested protein Allergen Skin allergy

15 A. Opsonic phagocytosis
Allergen Stimulate Antibody Cell A. Opsonic phagocytosis Combined opsonic activities D. ADCC of NK C. Effect of complement Cell injury ways of type II hypersensitivity

16 Change the function ofTarget cell
Antigen or hapten on cell Antibody (IgG, IgM) Activate complement Opsonic phagocytosis NK , phagocyte Stimulate / block Lyse target cell Destroy target cell ADCC Target cell injury Change the function ofTarget cell Mechanism of Type II hypersensitivity

17 Mechanism of type III hypersensitivity
Formation of the intermediate immune complex Deposition of the intermediate immune complex Tissue injury by the immune complex

18 common disease of type III hypersensitivity
1. Local immune complex disease Arthus reaction :Experimental local reaction, Necrotic vasculitis Ulcer Human local reaction: insulin-dependent diabetes mellitus (IDDM) 2. Acute systemic immune complex disease    serum sickness  Anti-serum → Ab+Ag → systemic tissue injury ,fever, arthritis, skin rash Pinicillin、Sulfanilamide Acute immune complex glomerulonephritis : Streptococcus infection 3. Chronic immune complex disease: SLE Rheumatoid arthritis :RF+IgG → Deposit on synovial membrane

19 Type IV hypersensitivity
characteristics of type IV hepersensitivity mechanism of type IV hepersensitivity common diseases of type IV hepersensitivity

20 Characteristics Interaction of primed T cells and associated antigen Infiltration of Mononuclear Cells, Inflammatory response

21 Mechanism of type IV hypersensitivity
Formation of effector and memory T cells Inflammation and cytotoxicity caused by effector T cells 1) Inflammation and tissue injury mediated by CD4+Th1 Release chemokines and cytokines Immune injury mainly caused by infiltration of mononuclear cells and lymphocytes 2) Cytotoxicity of CD8+


23 Common disease of type IV hypersensitivity
Infectious delayed type hypersensitivity OT( Old Tuberculin ) test Contact dermatitis Acute rejection of allogenic transplantation Same disease (SLE), multiple immune injury ,hypersensitivity involved Same drug (penicillin), several types of hypersensitivity


25 Sensitized T lymphocytes have secondary contact with the antigen (hapten)
conjugated with a protein and presented on the surface of an antigen presenting cell (APC). APCs are the Langerhans’ cells Presentation of the antigen by :Langerhans’ cell to CD4+ Th-1 type T lymphocyte Release of cytokines that produces T cell activation and the recruitment of other non-antigen specific T cells and macrophages to the site

26 inflammatory reaction : peak at 72 hours
clinically patch test reaction: localised area of eczema After 3–4 days, immunological mechanisms downgrade the reaction and it gradually fades away.

27 Standard series All patients are patch tested to a standard of allergens, such as the International, European, North American, or British Contact Dermatitis Group (BCDG) standard series

28 British Contact Dermatitis Group recommended standard series
Quaternium Nickel sulfate Methylchloroisothiazolinone Methylisothiazolinone Mercaptobenzothiazole Primin Sesquiterpene lactone mix Chlorocresol Bronopol Cetearyl alcoho Fucidic aci Tixocortol pivalate Budesonide Imidazolidinyl urea Diazolidinyl urea Methyldibromoglutaronitrile Ethylenediamine dihydrochl Neomycin sulfate Thiuram mix 1 Paraphenylenediamine Cobalt chloride Formaldehyde Rosin Quinoline mix Balsam of Peru Isopropyl PPD Wool alcohols Mercapto mix Epoxy resin Paraben mix PTBPF resin Fragrance mix

29 Contact dermatitis Allergens hazards in selected occupations
Bakers:Flavouring, oil, antioxidant Building trade workers:Cement (Cr, Co), rubber,resin, wood Caterers, cooks : fruit, veg,Veg/fruit, cutlery (Ni),rubber glove Cleaners: Rubber glove, nickel, Dental personnel : acrylate, Rubber, acrylate mercury Electronics assemblers: Cr, Co, Ni

30 Patch Test: Materials Finn chambers (shallow aluminium discs to hold allergens) Hypoallergenic acrylate tape. Allergens (diluted in various vehicles like petrolatum, water, ethanol, acetone, olive oil, etc.) India Indian Standard Battery approved by CODFI [Contact and Occupational Dermatoses Forum of India] is usually employed Marker pen





35 Indications of Patch Test
Allergic Contact Dermatitis Syndrome (ACDS) Atopic dermatitis Nummular dermatitis (nummular eczema) Seborrheic dermatitis presenting episodes of acute inflammation) Asteatotic eczema Stasis dermatitis Eczematous lesions around leg ulcer Pompholyx and/or dyshidrotic eczema Lichenification

36 Taking a history past and present occupation (possible contact with industria allergenor irritants) Hobbies (plants,animals) cosmetics, and current and previous treatments(potential medicamental hydrocortisone).

37 Selection of Patients 1. Taking less : 15 mg of oral steroid) 2. Not applying topical steroid on back for at least 1 week 3. Not having active or flared-up dermatitis 4. Not have been sunburned on back within last 2 weeks 5. Oral antihistamine can be continued during the process.

38 follow during the patch test procedure
Not to take bath or wash or wet the back To avoid tight underclothes To avoid exercise or activity causing sweating To avoid friction/scratching avoid strong sun exposure.

39 Patch Test: Methods upper back (excluding vertebra and scapular angle)
deltoid area (for small number of allergens) Site should be gently cleansed (with water and alcohol) and dried The top of patch test unit is marked and the protective foil removed and they are kept with aluminium chambers faced up The protective foil is fixed longitudinally along the edge of the patch test unit to facilitate handling


41 Reading the patch test reactions
fixed on the upper back ; left on for two days. removed, marked, read with another reading at four days problem in reading patch tests: differentiate irritantreactions (which have no diagnostic value) from allergic ones



44 Recording Patch test (la dou)
1 +=Weakreaction, nonvesicular,erythema,mild infiltration 2 + =Strongreaction, erythema, edema,vesicles 3 + =Extreme reaction, spreading ,bullous ,ulcerative 4 =Doubtful, faint erythema only 5 = Irritant reaction 6 =Negative 7 =Excited skin reaction 8 =Not tested

45 Recording patch test (0D)
+/− doubtful: faint erythema only + weak: erythema, maybe papules ++ strong: vesicles, infiltration +++ extreme: bullous

46 Patch Testing

47 variety of substances found both in the industrial allergen
Acrylates Adhesives Chromate Cement Cobalt Pigment Epoxy resins Paints/resins Ethylenediamine Formaldehyde Preservatives Detergents Nickel Electroplating jewellery manufacture Paraphenylenediamine Phenol formaldehyde

48 The possible side effects are explained
irritation on the back from the presence of the patches, the production of an excessive reaction worsening of the dermatitis in a number of cases, and actually sensitised by the process of testing








56 develop a “late” reaction—for example 1–3 weeks after( Gold salts cause this)
late reaction develops, often re-patch test after a suitable period (for example, four weeks)

57 The management of contact dermatitis is often difficult: overlapping factors
testing helps identify the allergens involved useful in dermatitis of the hands, face, feet

58 Most cases of occupational contact dermatitis: mixed etiology
Elimination of an allergen may not produce full resolution →often irritant /endogenous factors at play as well. Difficult to eliminate fully all contact with ubiquitous allergens such as nickel or colophony


60 Prick test

61 Diagnosis of allergic disease
most important • History taking • Physical examination • Evaluation of causative allergen Skin test : prick, intradermal, patch Serum specific IgE :RAST specific allergen provocation test :nasal, bronchial, oral

62 Focus of Allergy diagnosis
Is the patient atopic? Does allergy contribute to patient’s symptom? What are the clinical relevant allergens? →allergen avoidance → environmental control →immunotherapy, desensitization

63 Allergy History Taking
Main dominant symptoms Associated symptoms Frequency and severity of symptoms, impact on lifestyle Seasonal or perennial ? Triggering factors : allergic or non-allergic factor Occupation, hobbies Food, drug consumption history Possible allergen exposure in home Personal or family history of allergic disease Prior treatment response, side-effects

64 Skin test • Purpose identification of causative allergens
standardization of allergens : allergenic potency Advantages easy to perform, fast not expensive high sensitivity

65 Skin test : method • Prick test • Intradermal test • Scratch test

66 Skin prick test clean the test skin surface(back, forearm volar surface) with cotton moistened with 75% alcohol and dry up place a small drop of each test extract and positive/negative control solution 3-5cm apart prick with 25 or 26G needle and lift gently needle tip upward read the wheal and flare reaction 15min later-read


68 Skin prick test

69 Intradermal test clean the test skin surface(back, forearm volar surface) with 75% alcohol and dry up intradermal injection of allergen extract with 1ml syringe and 26G needle (approximately 2-4mm diameter bleb, 0.02ml injection) perform with positive/negative control solution read the wheal and flare reaction 15min later

70 Controls false positive -dermographism -needle irritation
false negative -medication (e.g. antihistamine) -underlying disease -technical error

71 Factors affecting skin test
• Allergen extract • Area of body -back >> arm -upper back >> lower back -ulnar side of arm >> radial side of arm • Age -significant wheal detect in infants -increase from infancy to adulthood -decline after age of 50 • Sex, Race • Seasonal variation

72 Drugs affecting skin test
• H1 antihistamine • Imipramies, Phenothiazines: > 10days • Systemic steroid short-term(=1wk) : no effect long-term : possible effect • H2 blocker, leukotriene antagonist, theophylline, beta-agonist: no clinical significance

73 Positive criteria Size of wheal and erythema(flare) prick test:
wheal size =3mm flare=10mm → regarded as clinically significant allergy intradermal test : wheal size =5mm

74 Interpretation Clinical relevancy
positive skin test ≠clinical allergic disease consider asymptomatic sensitization, insignificant cross-reaction (sensitization rate: 30-40% of general population) Correlation with other allergy diagnostic test Diagnostic value of skin test: inhalant : most cheapest and effective method for respiratory allergy food : low sensitivity drug : variable, low sensitivity except penicillin

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