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HANOI ECZEMA in children.ppt

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HANOI ECZEMA in children.ppt HANOI ECZEMA in children.ppt Presentation Transcript

  • Eczema in children Hugo Van Bever Department of Pediatrics National University Singapore APAPARI Workshop, Hanoi, May 2008
  • Eczema in Singapore Children Results of ISAAC Questionnaire Survey Wang XS et al. Arch Dis Child. 2004, Tan TN et al., Pediatr Allergy Immunol. 2005, Asian Pac J Allergy Immunol. 2006
    • 1 year period prevalence of 20.8% from a questionnaire cum clinical examination survey in schoolchildren
    • (Tay YK et al Br J Dermatol 2002)
  • 6/7 year-olds ISAAC Asthma Hay fever Eczema Asher et al, Lancet 2006 Phase 1 vs. phase 3 Country Inc D Same Inc D Same Inc D Same Hong Kong * * * Indonesia * * * Japan * * ? ? ? Malaysia * * * Singapore * * * S-Korea * * * Taiwan * * * Thailand * * * Australia * * *
  • Prevalence of AD in 6 – 7 yr-old children (ISAAC) H. Williams et al. JACI, 121, 947, April 2008.
  • Mechanisms of Eczema in Children
    • 1. ALLERGY
    • 2. SKIN BARRIER DYSFUNCTIONS
    • 3. CHRONIC INFECTION
    • 4. AUTO-IMMUNITY (?)
    = complex interplay according to pt. and age
  • Incidence of eczema at 2 years in children given probiotics from birth Kalliomaki M, Lancet. 2001; 357:1076 50% decrease… IgE-mediated reactions persist !
  • AD and BMT
    • Complete correction of the Wiskott-Aldrich syndrome by allergenic bone-marrow transplantation. Parkman et al. NEJM 1978, 298, 921.
    • 2. Transfer of atopy following bone marrow transplantation. Bellou A, et al. Ann Allergy Asthma Immunol 1997, 78, 513.
  • Atopic dermatitis
    • 1. SKIN DISORDER
    • 2. ALLERGIC DISEASE
    • 3. Combination ?
  • Eczema in SE-Asia more severe
  • The Asian Skin
    • Ethnic differences in the pattern of skin diseases seen in a dermatology department – atopic dermatitis is more common among Asian referrals in Leicestershire. Sladden et al. Clin Exp Dermatol 1991, 16, 348.
    • The effect of lifestyle on wheeze, atopy, and bronchial hyperreactivity in Asian and white children. Carey et al. Am J Respir Crit Care Med. 1996, 154, 537.
    • Atopic dermatitis in children in the United States, 1997 – 2004: visit trends, patient and provider characteristics, and prescribing patterns. Horii et al. Pediatrics 2007, 120, e527.
    AD in Asians… 1. more common 2. more severe (?) UK US US
  • Is atopic dermatitis, an allergic disease ? YES, BUT…
  • Eczema SKIN BARRIER DYSFUNCTIONS
  • New perspectives on epidermal barrier dysfunction in atopic dermatitis: Gene–environment interactions.
    • Michael J Cork et al. J Allergy Clin Immunol 2006, 118, 3 – 21.
    “… on the importance of epidermal barrier dysfunction in genetically predisposed individuals …”
  • Skin barrier dysfunction in AD
    • 1. dry skin – increased transepidermal water loss
    • 2. reduced content of ceramides
    • 3. changes in stratum corneum pH level
    • 4. overexpression of chymotryptic enzyme
    • “ Stratum corneum chymotryptic enzyme (SCCE) “
    • 5. altered keratinocyte cytokine profile
  • 1. Chymotrypsin (SCCE) 2. Filaggrin Two (of the many) new players in eczema…
  • Stratum corneum, corneodesmosomes and SCEE Cork et al. JACI, 2006, 118, 3-21 SCCE  breakdown of corneodesmosomes
  • Corneodesmosomes and exogenous Proteases Cork et al. JACI, 2006, 118, 3-21 Desquamation Thinning of the skin ECZEMA
  • Filaggrin gene
    • - FLG is located within “the epidermal differentiation complex (EDC) on chromosome 1q21.
    • - Function: to aggregate keratin filaments  formation of stratum corneum  maintaining the barrier function of the skin.
    • - Associated with ichtyosis, AD, and psoriasis
  • JACI 2007, 120, 1406 – 1412.
  • FLG polymorphisms
    • R501X
    • 228del4
    Complete loss of FLG expression ICHTHYOSIS VULGARIS (= FLG null alleles)
  •  
  • J Allergy Clin Immunol, 2008, 121, 940 - To investigate the role of 5 common FLG null mutations in childhood AD - n = 811 children in UK (non-selected group) - Prevalence of AD = 24% - CONCLUSION : FLG mutations are significantly associated with mild-to-moderate atopic eczema in childhood, with a recessive pattern of inheritance.
  • Phenotype (ECZEMA) Environment Genes DEVELOPMENT (EPIGENETICS) Dynamics of gene expression (methylation processes) Area of new research…
  • Impaired skin epidermal barrier allergen penetration  IgE ALLERGIC MARCH Eczema severity Asthma Rhinitis (different type of allergy?) = 2 nd event…
  • Extrinsic versus intrinsic eczema IgE Altered skin barrier EXT INT AD
  • AD:  2 features severe allergy severity of AD Skin barrier features allergy The environment
  • The rising prevalence of atopic eczema and environmental trauma to the skin. Cork et al. Dermat Pract 2002, 10, 22. Increased skin barrier dysfunctions UK data 1960 - 1981 1995 - 2001 Personal use of soap -detergent 76 million £ 453 million £ Water for personal washing 11 L /day 51 L/day
  • Pathogenesis of AD SKIN BARRIER DYSFUNC TIONS ALLERGY genes genes environment environment
  • HYPOTHETIC MODEL OF AD
    • PHASE 1 : Non-allergic inflammation
    • - ichtyosis – pruritus
    • - auto-immunity (?)
    • - other (viruses?)
    • PHASE 2 : Allergic inflammation
    • - food (  through urticaria)
    • - inhalants (type IV immune reaction)
    • PHASE 3 : Infectious inflammation
    • - Staph colonization
    • - Viral colonization
    early infancy early childhood late childhood adulthood
  • HYPOTHETIC MODEL OF AD
    • PHASE 1 : Non-allergic inflammation
    • - ichtyosis – pruritus
    • - auto-immunity (?)
    • PHASE 2 : Allergic inflammation
    • - food (  through urticaria)
    • - inhalants
    • PHASE 3 : Infectious inflammation
    • - Staph colonization
    • - Viral colonization
    early infancy early childhood late childhood adulthood moisturizing allergen avoidance antiseptics > antibiotics
  • Conclusion…
    • 1. Complex disease  different types
    • 2. Not only allergy… there is more
    • 3. More studies on “start” of AD
    • 4. Treatment: according to age