Effect of Omalizumab in the Skin of Food Allergy Patients

Inclusion Criteria: * Participant and/or parent/legal guardian must be able to understand and provide informed consent and/or assent, as applicable. * Male or female, 1-55 years old at screening. * Total IgE level within 1 year of screening and weight at screening visit that together result in an eligible omalizumab dose according to the dosing table for FA (Appendix 8). * Participant must meet the following clinical FA criteria: Food sensitization to peanut, hen's egg, a tree nut, sesame seed, cow's milk, wheat, or soy, within 1 year of screening AND experience dose-limiting, IgE mediated symptoms at or before 444mg of food protein cumulatively during screening OFC to peanut, hen's egg, a tree nut, sesame seed, cow's milk, wheat, or soy. * If female of child-bearing potential, must have a negative urine or serum pregnancy test. If participating as a healthy control, self-report of pregnancy status is acceptable. * For women of child-bearing potential, must agree to remain abstinent (refrain from heterosexual intercourse) or use acceptable contraceptive methods (barrier methods or oral, injected, or implanted hormonal methods of contraception or other forms of hormonal contraception that have comparable efficacy) during the treatment period and for 60 days after the last dose of study drug. * Be willing to be trained on the proper use of an epinephrine autoinjector and be willing to always have epinephrine autoinjector immediately available for the duration of the study. Exclusion Criteria: * Inability or unwillingness of a participant and/or parent/legal guardian to give written informed consent and/or assent or comply with the study protocol. * Clinically significant laboratory abnormalities at Screening. * Sensitivity or suspected/known allergy to any ingredients (including excipients) of the active OFC material (other than the study food), or drugs related to omalizumab (e.g., monoclonal antibodies, polyclonal gamma globulin). * Poorly controlled AD at Screening, per the PI's discretion. * Poorly controlled or severe asthma/wheezing at Screening * History of severe anaphylaxis (defined as neurological compromise or requiring intubation) to a study food that is to be used for qualifying OFC in this study. * Treatment with oral, intramuscular (IM), or intravenous (IV) steroids of more than two days for an indication other than asthma/wheezing within 30 days of Screening. * Currently receiving oral, IM, or IV corticosteroids, tricyclic antidepressants, or β-blockers (oral or topical). * Past or current history of cancer, or currently being investigated for possible cancer. * Previous adverse reaction to omalizumab. * Past or current history of any immunotherapy to the OFC food (e.g., oral immunotherapy \[OIT\], sublingual immunotherapy \[SLIT\], or patch/epicutaneous immunotherapy \[EPIT)\] within 4 months of Screening. * Treatment with monoclonal antibody therapy, such as omalizumab (Xolair®), dupilumab (Dupixent®), benralizumab (Fasenra™), mepolizumab (Nucala®), reslizumab (Cinqair®), or other immunomodulatory therapy within four months of Screening. * Currently on "build-up phase" of inhalant allergen immunotherapy (i.e., has not reached maintenance dosing). Individuals tolerating maintenance allergen immunotherapy can be enrolled. * Inability to discontinue antihistamines for the minimum wash-out periods required for SPTs or OFCs * Current participation in another therapeutic or interventional clinical trial or participation within 90 days of Screening. * Use of investigational drugs within 24 weeks of Screening. * Pregnant or breastfeeding or intending to become pregnant during the study or within 60 days after the last dose of omalizumab. * Have any skin disease other than AD that might compromise the stratum corneum barrier. * History of serious life-threatening reaction to tape or adhesives. * Healthy Control Participants (non-Food Allergy participants) may not have atopic dermatitis, autoimmune, or other conditions which, in the opinion of the PI, could confound the results of the study assessments or samples.