Allergic diseases include atopic dermatitis, food allergy, asthma, and allergic rhinitis. Atopic or allergic diseases are becoming more and more prevalent in the population.
- Food allergy in its most severe form may manifest as anaphylaxis.
- These conditions may present in a variety of ways as described below.
- Atopic dermatitis
- Atopic dermatitis (or eczema) is characterized by chronic, relapsing, pruritic inflamed skin, which is often erythematous, xerotic, and/or excoriated.
- Atopic dermatitis may occur in isolation without other atopic diseases or it may be the beginning of the “atopic march” preceding the onset of other atopic conditions, which may include food allergy, asthma, and/or allergic rhinitis.
- Refers to hives or the erythematous wheals that occur when histamine is released from mast cells
- May be caused by a number of triggers
- Viral infection is the most common cause of urticaria in children.
- The allergic child may develop urticaria when an antigen such as a food causes IgE-mediated release of mast cell mediators.
- Food allergy
- Presents with an IgE-mediated reaction after exposure to a food to which the child is sensitized
- Reactions may involve any number of allergic symptoms, including urticaria, lip or tongue swelling, closing of the throat, wheezing, shortness of breath, hypotension, lethargy, repeated vomiting after allergen ingestion, diarrhea, or any combination of the above.
- The most common food allergens include cow’s milk, egg, peanut, tree nuts, wheat, soy, fish, and shellfish.
- Food allergy should be distinguished from food intolerance, which does not have an IgE basis and does not carry a risk of anaphylaxis.
- An obstructive airway disease characterized by recurrent wheezing, bronchoconstriction, increased mucous production, and airway inflammation
- Asthma is one of many potential causes of wheezing in children.
- Wheezing with RSV and human rhinovirus infection are associated with the development of asthma.
- Allergic rhinitis and conjunctivitis
- A condition in which children are sensitized to perennial allergens, seasonal allergens, or both
- Perennial allergens include dust mite, cockroach, animal dander, and some molds.
- Seasonal allergens include tree pollens, grass pollens, weed pollen, ragweed pollen, and other molds.
- Symptoms may include watery eyes, itchy eyes, rhinorrhea, nasal discharge, itchy nose, sneezing, postnasal drip, throat clearing, headache, sinus pressure, nasal obstruction, mouth breathing, or snoring.
- Symptoms may be seasonal, year-round, or triggered by exposure to specific allergens (such as cats or dogs).
- Children who do not have a family history of atopy have approximately a 25% chance of being atopic.
- For children with at least one parent who is atopic, the risk of atopy approximately doubles compared to the general population.
Most of these allergic conditions are IgE mediated, and all result from a complex interaction between multiple genetic and environmental factors.
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