Patch Test By H.Eshaghi M.D

2. Patch Test By H.Eshaghi M.D

3. IRRITANT CONTACT DEMATITIS • 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 Contactdermatitis : • 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: 18-24 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. Theoreticalbasis 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 IVHypersensitivity

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 : Allergen The lack of Serum IgAprotein hydrolase Undigested protein • Skin allergy

15. 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. 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 Arthusreaction ：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 • commondiseases 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) Cytotoxicityof 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 Grouprecommended standard series Quaternium Nickel sulfate MethylchloroisothiazolinoneMethylisothiazolinone Mercaptobenzothiazole Primin Sesquiterpenelactone mix Chlorocresol Bronopol Cetearylalcoho Fucidicaci Tixocortolpivalate Budesonide Imidazolidinyl urea Diazolidinyl urea Methyldibromoglutaronitrile Ethylenediaminedihydrochl • Neomycin sulfate • Thiuram mix 1 • Paraphenylenediamine • Cobalt chloride • Formaldehyde • Rosin • Quinoline mix • Balsam of Peru • Isopropyl PPD • Wool alcohols • Mercapto mix • Epoxy resin • Parabenmix • 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 industriaallergenor 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 backwithin last 2 weeks 5. Oral antihistaminecan 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 • jewellerymanufacture • 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