CAN WE STOP THE ALLERGIC MARCH? Secondary & Tertiary Prevention of Allergy
(Joanna Christine A. Vicencio, M.D.)

The atopic march refers to the natural history of allergic disease that involves the switching of one clinical expression of allergy to another in the progressive stage of life. It begins early in life with food allergy and atopic dermatitis leading to the development of allergic respiratory diseases such as allergic rhinitis and bronchial asthma in later life. In our attempt to stop the allergic march, secondary and tertiary prevention strategies remain an essential part of treatment.
 
Secondary prevention of allergic disease aims to halt the development of allergic disease in sensitized individuals. It likewise prevents the progression of allergic disease from one form to another. However, only a small number of true secondary prevention trials exist. These include pharmacologic measures such as the administration of Ketotifen to with atopic dermatitis to decrease the incidence of asthma. The Early Treatment of the Atopic Child (ETAC) study found that Cetirizine was able to delay or prevent the onset of new sensitization in monosensitized individuals. It also prevents the development of asthma in patients with allergic rhinitis. Environmental control of inhalant allergens particularly dust mites in high risk allergic children reduced the incidence of sensitization to dust mites and decreased allergic symptoms.
 
Tertiary prevention aims to alleviate and control symptoms in individuals who have established allergic disease such as atopic dermatitis, allergic rhinitis and atopic asthma. Early diagnosis is imperative if prevention strategies are to be initiated effectively.
 
Atopic dermatitis is a chronic inflammatory skin disorder that begins during infancy. Treatment and control of atopic dermatitis involve allergen and trigger avoidance such as dietary restriction in patients with established food hypersensitivity, avoidance of exposure to inhalants allergens such as house dust mites in older children and adults and avoidance of exposure to irritants such as chemicals in soaps and rough and wooly clothing. Systemic and topical treatment to control symptoms include the use of emollients, topical corticosteroids, antihistamines, antimicrobials, topical calcineurin inhibitors and phototherapy for refractory cases.
 
Allergic rhinitis results from inflammation of the nasal mucosa due to an IgE-mediated mast cell degranulation and mediator release leading to sneezing, rhinorrhea, itch and nasal blockage. Preventive measures to control allergic rhinitis include allergen avoidance in patients who have been proven to be allergic to dust mites, domestic pets and pollens. Avoidance of irritants such as smoke, pollutants, perfume and temperature change in patients with active rhinitis who exhibit nasal hyper-reactivity is also advised. Pharmacotherapy includes the use of antihistamines, corticosteroids, anti-leukotrienes, decongestants and chromomes.
 
Bronchial asthma is the most common chronic childhood disease in many countries. Atopic asthma is due to an IgE-mediated inflammation of the airways causing episodes of shortness of breath, cough, wheezing and chest tightness. The prevention of exacerbations entails avoidance of multiple triggers including allergens, pollutants and viral infections. Pharmacologic measures to treat and control symptoms depends on the severity and control of the disease. These includes the use of the ff: corticosteroids, anti-leukotrienes, b2-agonist, theophylline, anticholinergics, chromomes and most recently anti-IgE therapy. Allergen specific immunotherapy is proven to be effective in controlling symptoms of patients with allergic rhinitis and/or atopic asthma