Allergic disorder

Allergic disorder is characterised by immune reactions to normally harmless substances, leading to respiratory symptoms.

• Pollen: from trees, grasses, and weeds.
• House dust mites: microscopic creatures living in household dust.
• Animal dander: tiny, even microscopic, flecks of skin shed by cats, dogs, rodents, birds, and other animals with fur or feathers.
• Moulds: fungi that can be found both indoors and outdoors.

• Wheezing and coughing.
• Shortness of breath.
• Runny or stuffy nose.
• Sneezing.
• Red, itchy, or watery eyes.
• Chronic sinusitis.

Patch Testing

• Used primarily to identify substances causing contact dermatitis.
• Allergens are applied to the skin via patches; reactions are read after 48 hours.
• Common allergens tested: metals (e.g., nickel), rubber, medications, fragrances, preservatives, hair dyes, chemicals.

Skin Prick Testing (Pin Prick Testing)

• Small amount of suspected allergen is placed on the skin using a tiny needle prick.
• If allergic, a raised, red area (wheal) will appear within 20 minutes.
• Commonly used for environmental allergens, foods, insect stings, and some medicines.

Blood Tests

• Total IgE levels: Elevated in many allergic conditions but non-specific.
• Allergen-specific IgE: Can determine sensitivity to specific allergens.
• Complete Blood Count (CBC): Eosinophilia may be present in allergic disorders.

• Allergen Avoidance: Identification and minimisation of exposure to the offending allergens.
• Antihistamines: Reduce allergic reactions by blocking histamine release.
• Inhaled Corticosteroids: For respiratory symptoms like asthma due to allergies.
• Allergen Immunotherapy: Gradual exposure to increasing amounts of allergen to modulate immune response. Effective for certain allergies like grass pollen.

• Asthma exacerbation.
• Chronic sinusitis.
• Anaphylaxis: Severe, potentially life-threatening allergic reaction. Requires immediate medical attention.

• Allergic disorder is characterised by immune reactions to normally harmless substances.
• Common respiratory symptoms include a classic wheeze, coughing and sometimes shortness of breath.
• Investigation includes determining allergen with skin prick or patch testing and identifying allergic status through elevated IgE levels on blood tests.
• A priority for management is avoidance or gradual exposure to the allergen and relieving symptoms.
• Management is important to prevent serious, life threatening complications such as anaphylaxis.