Contact dermatitis - Prof. Ortega Martell - Prof. Sánchez-Borges

Contact dermatitis - Prof. Ortega Martell - Prof. Sánchez-Borges

1. Contact Dermatitis Guangzhou , China. June 2019 China Medicine Education Association Prof. Mario Sánchez Borges Venezuela Prof. J.A. Ortega Martell México

2. Objectives Introduction Definition Epidemiology Pathogenesis Diagnosis / Diagnostic Criteria / Lab Findings Differential Diagnosis / Pediatric Issues Treatment Summary / Conclusions

3. Introduction Contact Dermatitis (CD) : Occurs after direct or indirect contact with substances that are harmful to the skin Irritant and allergic contact dermatitis are the most common forms More than 4000 contact irritants and allergens have been described Goldenberg A, et al. J Allergy Clin Immunol Pract 2015;3:661-7.

4. Introduction Contact Dermatitis ( CD ): Should be considered in the differential diagnosis of any patient presenting with a pruritic skin rash with erythematous papules , vesicles , or eczematous rash with crusted lesions . Chronic CD is associated with secondary skin changes such as lichenification , fissuring , thickening , and scaling . Bernstein D. J Allergy Clin Immunol Pract 2015;3:652-8 Introduction

5. Contact Dermatitis

6. Classification Admani S, Jacob SE. Curr Allergy Asthma Rep (2014) 14:421 Classification

7. Definition Irritant Contact Dermatitis : It does not require prior sensitization , but rather is caused by direct damage to keratinocytes by an irritating substance ( e.g ., an alkaline or acidic chemical ). This leads to a localized release of proinflammatory cytokines and the subsequent development of an eczematous dermatitis Admani S, Jacob SE. Curr Allergy Asthma Rep (2014) 14:421 Definition

8. Definition Allergic Contact Dermatitis : Type IV ( delayed ) hypersensitivity reaction , which requires a prior sensitization , and elicitation Allergic contact dermatitis in children is increasing Sensitization to contact allergens may already begin at an early age Patch testing is the gold standard diagnostic test Admani S, Jacob SE. Curr Allergy Asthma Rep (2014) 14:421 Definition

9. Epidemiology The data on prevalence of contact allergy among children visiting dermatology clinics vary between 15 % and 71 %. Nevertheless , the true prevalence of sensitization continues to be grossly underreported because of deficiencies in reporting and tracking. Goldenberg A, et al. J Allergy Clin Immunol Pract 2015;3:661-7. E pidemiology

10. Epidemiology The most common contact allergens in children are: metals ( nickel , cobalt , and chromate ) fragrances preservatives neomycin rubber chemicals p - tert - butylphenol -formaldehyde resin de Waard -van der Spek et al. Pediatric Allergy and Immunology 24 (2013) 321–329 E pidemiology

11. Allergen Common Source of Exposure Positive Rate of Patch Test (%) Nickel Jewelry, metal items, coins 19.0 Balsam of Peru Fragrances, spices 11.9 Fragrance mix Fragrances 11.5 Quaternium 15 Preservative 10.3 Neomycin Topical antibiotic 10.0 Bacitracin Topical antibiotic 9.2 Formaldehide Preservative 2.0 Cobalt chloride Metal 8.4 Methyldibromoglutaronitrile / phenoxyethanol Preservative 5.8 p- Phenylenediamine Permanent hair dye 5.0 Potassium dichromate Metallic salt in wet cement and leather 4.8 Carba mix Rubber accelerator 3.9 Thiuram mix Rubber accelerator 3.9 Diazolidinylurea Preservative 3.7 2-Bromo-2-nitropropane-1,3-diol Preservative 3.4

12. Pathogenesis Allergic contact dermatitis (ACD) results from a biphasic , delayed ( type IV) hypersensitivity reaction comprising primary sensitization and secondary elicitation : Non Sensitized Sensitization Elicitation Allergen ( hapten + carrier ) Allergen ( hapten + carrier ) Pathogenesis

13. Pathogenesis The sensitization phase is characterized by an exogenous allergen entering the epidermis through an impaired skin barrier . These allergens then bind with selfproteins to create complete antigens that are taken up and presented by dendritic cells on the cell surface with major histocompatibility complexes (MHC ). Admani S, Jacob SE. Curr Allergy Asthma Rep (2014) 14:421 Pathogenesis

14. Pathogenesis The elicitation phase occurs upon repeated exposure to the allergen at which time a clinical dermatitic response occurs . The repeated exposure can occur trans-epidermally or systemically through ingestion , inhalation , or intravenous entry . Admani S, Jacob SE. Curr Allergy Asthma Rep (2014) 14:421 Pathogenesis

15. Pathogenesis Pathogenesis Sensitization phase Elicitation phase

16. Pathogenesis Direct cutaneous exposure to allergens / haptens ( lipophilic molecules of < 500 Daltons ) Migration and maturation of dendritic cells D endritic cells interact with T lymphocytes Diffusion of allergens / haptens into the skin and activation of sensitized T lymphocytes ( Th 1 , Tc, Th 17 , Th 22 , Th 9 ) Pathogenesis

17. Pathogenesis APC  Th 1  M f  Inflammation APC  Th 17  Neu  Inflammation Pathogenesis Tissue Damage

18. Pathogenesis Tc lymphocyte dependent cell cytotoxicity APC  Th 1  Tc  Apoptosis, Necrosis Pathogenesis Tissue Damage

19. Diagnosis Allergic Contact Dermatitis classically presents as a localized , erythematous , eczematous eruption , often with geometric or linear patterns corresponding to sites of contact with the allergen . The location of the reaction can be a useful clue about the inciting allergen , especially when the presentation is limited . Goldenberg A, et al. J Allergy Clin Immunol Pract 2015;3:661-7. Diagnosis

20. Diagnosis Goldenberg A, et al. J Allergy Clin Immunol Pract 2015;3:661-7. Diagnosis

21. Diagnosis Epicutaneous patch testing is the criterion standard for the diagnosis of ACD: Remove patch at 48 Hours Interpret Results at 72 and 96 Hours Diagnosis

22. Diagnosis Patch Testing : Panels with common contact allergen components Diagnosis

23. Diagnosis Diagnosis

24. Diagnosis Diagnosis

25. Diagnosis Diagnosis

26. Patch Test Patch test

27. Patch Test Patch test

28. Patch Test Patch test

29. Patch Test Patch test

30. Patch Test Patch test

31. Differential Diagnosis Allergic vs Irritant Contact Dermatitis Differential Dx

32. Differential Diagnosis Patch test interpretation Differential Dx

33. Differential Diagnosis Bernstein D. J Allergy Clin Immunol Pract 2015;3:652-8 Differential Dx

34. Differential Diagnosis Bernstein D. J Allergy Clin Immunol Pract 2015;3:652-8 Differential Dx

35. Treatment Topical corticosteroids are usually sufficient short- term systemic steroids : more severe dermatitis antibiotics occassionally needed Irritants - avoid while healing Avoidance measures don’t forget substances that cross-react find substitutes for necessary products skin protection to prevent repeat exposure Bernstein D. J Allergy Clin Immunol Pract 2015;3:652-8 Treatment

36. Summary / Conclusions Allergic CD common problem in children Age-appropriate history is key to dx Potential sensitizers are in diapers , hygiene products , cosmetics , sun blocks, textiles and dyes , medications , tattoos and sporting accessories Patch testing sometimes needed Treatment : corticosteroids acutely , and then avoidance measures Summary / Conclusions

37. Thank You Guangzhou , China. June 2019

38. Questions ?