Atopic Dermatitis (AD) and Food Allergy
Condition: Atopic Dermatitis (AD); Non-atopic Healthy Controls
MeSH terms: Dermatitis, Atopic; Dermatitis; Eczema; Food Hypersensitivity
Study type: Observational

Summary: 
      This is a prospective, single center, clinical mechanistic pilot clinical research study.
      Participants will not receive any investigational agent. The investigators will examine
      whether children with atopic dermatitis (AD) and food allergy have a different skin barrier,
      microbiome, epidermal transcriptome, and epidermal lipid composition than children with AD
      and no food allergy and non-atopic (NA) children. Participation involves a single study
      visit.
    

Detailed description: 
      Atopic Dermatitis (AD) is a chronic inflammatory skin disorder in which the skin becomes
      extremely itchy and is susceptible to recurrent skin infections. AD is thought to occur from
      a combination of immunological, genetic, and environmental factors.

      Those with atopic dermatitis (AD) often have food allergy and Staphylococcus aureus (S.
      aureus) colonization of the skin. There is evidence suggesting that skin barrier dysfunction,
      measurable as increased transepidermal water loss (TEWL), is a predisposing factor to food
      sensitization and food allergy from epicutaneous penetration of environmental food allergens.
      Furthermore, the investigators for this study have identified that AD children with food
      allergy, especially peanut allergy, are colonized with Staphylococcus aureus. However, only
      half (50%) of children with AD have food allergy or S. aureus colonization, suggesting there
      are other factors accounting for food allergy. There have been no previous studies of TEWL
      or, microbial or molecular profiling of the skin in those with AD prone to food allergy
      versus AD without food allergy.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children ages 4-17 years, inclusive. Enrollment will include 20 AD children with food
        allergy to peanut, 20 AD children without a history of food allergy, and up to 20 NA
        children. The study requires that AD participants with peanut allergy meet the 95% positive
        predictive value for skin prick test (≥ 8 mm wheal) for peanut allergy. Food allergic AD
        participants will be allowed to have other food allergies in addition to peanut. A subset
        of children with AD whose disease is too severe to stop prohibited medications as defined
        in the protocol will be excluded. NA children will serve as a healthy control group for the
        AD study participants. Enrollment is to children since AD and food allergies are more
        prevalent among children, and adult onset AD and/or food allergy is a different phenotype.
      
Biospecimen description: 
      Serum, Plasma, DNA, Skin tape strip samples and any derivatives, Skin swabs and any
      derivatives, Stool samples and any derivatives
    
Keywords: skin barrier function; microbiome; transepidermal water loss (TEWL); epidermal transcriptome; epidermal lipid composition