Allergic Reactions Among Psoriatic Patients

• Psoriasis is a chronic inflammatory disease with an unknown etiology.
• Allergic disease is believed to co-exist with psoriasis.
• Psoriasis that exists for a prolonged period leads to break in the epidermal barrier and increased exposure to allergens.
• Hypersensitivity to allergens is found to correlate with the intensity of disease symptoms.

In a study conducted by Maria W and colleagues titled "Analysis of Selected Allergic Reactions among Psoriatic Patients", the relation between hypersensitivity to allergens and psoriasis is determined. Psoriasis exists in nearly 2 to 3% of the entire population and there are numerous studies that exist about it, but there is no definite etiology associated with the disease. Some known facts on the etiology of the psoriasis include:

• Genetic, immunologic and environmental factors play an important role in etiology.
• Immunological process plays an important role in the pathogenesis of psoriasis.
• Allergic reactions are believed to co-exist with psoriasis due to disease complexity.
• Prolonged disease leads to a breakdown in the epidermal barrier, resulting in the entry of allergens.

The current study aimed at studying the contact, food and inhalant allergic reactions among patients with psoriasis. 80 patients with psoriasis were included in the study, aged between 18 and 60 years. The study participants were tested for the following:

• Total IgE antibodies.
• Allergen-specific antibodies (asIgE).
• Standard epidermal tests.
• Atopic patch test- This contained allergen extract of dust mites, birch pollen, molds, fungus, pollen, hairs of dog and cat.
• The allergens that were tested included egg, wheat flour, soy, hazelnut , dust mites, cat, horse, cod, carrot, milk, potato, and dogs.

The study results showed that there was a higher concentration of IgE, especially for the pollen of trees, timothy, rye, and birch. Higher concentration of IgE antibody was found in Cladosporium herbarium, Dermatophagoides pteronyssinus and Alternaria alternate. There was food allergy towards potato and carrot and cross-reactivity existed between potato or carrot and the pollen of Birch, Timothy, and Rye. There was a mild contact allergy towards  Nickel sulphate, Lanolin, and Cobalt chloride.

This study also highlighted that the concentrations of IgE antibody correlated with the intensity of disease progression in patients with psoriasis.

The suggested pathogenesis of psoriasis is due to the dendritic cells presenting T lymphocytes with self-antigens in individuals who have a genetic predisposition for psoriasis. Activated T lymphocytes derived from patients with psoriasis have been shown to induce psoriasis in mice but not those derived from healthy people. Moreover, the injected T-lymphocytes increased keratinocyte proliferation when injected.

Initially, it was believed that Th1 cells mediated the immune response that leads to psoriasis and other auto-immune disorders. However, recent studies have found that Th17 cells also aid in mediating the response.

Though immune reactions are triggered by both an allergy as well as psoriasis, the current study by Maria found a weak correlation of an allergic reaction with psoriasis pathogenesis. However, hypersensitivity correlates with the intensity of the disease symptoms.

This aids in controlling flare-ups in psoriasis patients by re-instating the need to control exposure to allergens.

Controlling Allergy in Psoriasis Patients

• Identify the allergen: Allergen identification is made using a patch test or by injecting the allergen into the skin and then waiting for an allergic reaction.
• Avoiding allergen exposure: Though there are some allergens which cannot be avoided, there are certain allergens like food allergens which can be avoided.
• Immediate treatment: When exposed to an allergen that could trigger a psoriasis flare-up, immediate treatment measures should be carried out.

Psoriasis is a chronic inflammatory disease that co-exists with allergic reactions in many patients. Therefore, effective treatment of an allergic reaction will aid in reducing the intensity of the infection.

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Source-Medindia