Allergy Allergy is a specific immunological reaction to a normally harmless substance, one that does not bother most people. It is often characterized by redness of the skin, warmth, swelling, and pain and inflammation of respiratory track..
Allergen A substance capable of sensitizing the body in such a way that an unusual response occurs, in hypersensitive person
TYPES OF ALLERGENAllergens that cause allergic reactions include: Pollens House dust mites Mold spores Food Latex rubber Insect venom Medicines Fragrance
INTRODUCTION The term allergy was first defined in 1906 by von Pirquet in describing a changed reaction in the body. An unusual response of a person to a substance that is harmless to others, the individual is said to be allergic. 500 million people suffer from food allergy 300 million suffer from asthma Excessive cause of allergy is over-sanitation, utilization of antibiotics & less exposure to viruses and bacteria in childhood. Allergy involves an exaggerated response of the immune system.
Immunology Of Allergy• Elevated IgE levels seen in allergy and parasitic infection.• Binds to mast cells and basophils.• Often specific for harmless environmental factors – allergens.
Cont….. Immune system activated when pathogen enters B-cells produce antibodies-immunoglobulin Five types of immunoglobulin in which IgE is important in allergic reaction. Attached to mast cell at determine site-crosslinking
COMMON SYMPTOMS OF ALLERGYAFFCTED ORGANS SYMPTOMSNose Swelling of nasal mucosaSinuses Allergic sinusitisEyes Redness and itching of conjunctiva.Airways Sneezing, coughing, bronchoconstriction, wheezing, dypsea and asthma.Ear Feeling of fullness, possibly pain and impaired haring.Skin Rashes such as eczema and hivesGastrointestinal pain Abdominal pain, bloating, vomiting and diarrhea
Causes of Allergy Foods Non-food proteins Toxins interacting with proteins Airborne allergen Genetic basis
Mechanism of allergyo Acute responseo Late-phase response
Atopic dermatitis(Eczema) Chronic inflammatory skin disorder Affects at least 15% of children & up to 10% of adults Atopic dermatitis is often the first manifestation of allergic disease & many patients may develop allergic rhinitis and asthma later in life Symptoms: rashes are dry, scaly and itchy In infants & young children, the rashes appear on the face, neck, cheeks and scalp In older children & adults-appear on the folds of the forearms, the inner elbows and behind the knees
Factors that make the symptoms worse include temperature, humidity, irritants, infections, food, inhalant and contact allergens and emotional stress Treatment: Topical corticosteroids , lifestyle changes & the use of medications
Contact Eczema Contact eczema is a localized reaction that includes redness, itching & burning in areas where the skin has come into contact with an allergen Due to the vast number of substances with which individuals have contact, it can be difficult to determine the trigger for contact dermatitis. The condition is sometimes referred to as allergic contact eczema , if the trigger is an allergen and irritant contact eczema. People who have a history of allergies have an increased risk for developing contact eczema.
Seborrheic Eczema Seborrheic eczema is a form of skin inflammation of unknown cause. The signs and symptoms include yellowish, oily, scaly patches of skin on the scalp, face & occasionally other parts of the body. Dandruff and "cradle cap" in infants. It is common place for seborrheic dermatitis to inflame the face at the creases of the cheeks and/or the nasal folds. This condition tends to run in families. Emotional stress, oily skin, infrequent shampooing, and weather conditions are felt to be factors for developing seborrheic eczema. One type of seborrheic eczema is also common in people with AIDS.
Nummular Eczema Nummular eczema is characterized by coin-shaped patches of irritated skin -- most commonly located on the arms, back, buttocks, and lower legs -- that may be crusted, scaling, and extremely itchy. occurs most frequently in elderly men and women. usually a chronic condition. A personal or family history of atopic dermatitis, asthma, or allergies increases the risk of developing the condition.
Neurodermatitis chronic skin inflammation caused by a scratch-itch cycle that begins with a localized itch that becomes intensely irritated when scratched. Women are commonly affected, frequent in people 20- 50 years of age. This form of eczema results in scaly patches of skin on the head, lower legs, wrists, or forearms. Over time, the skin can become thickened and leathery.
Stasis Dermatitis skin irritation on the lower legs, generally related to the circulatory problem known as venous insufficiency, in which the function of the valves within the veins has been compromised. exclusively in middle-aged and elderly people, with approximately 6%-7% of the population over 50 years of age being affected by the condition. The risk is higher in advancing age. Symptoms include itching and/or reddish-brown discoloration of the skin on one or both legs. ulcers may develop in affected areas. lead to an increase in fluid buildup (edema) in the legs.
Dyshidrotic Eczema irritation of the skin on the palms of hands & soles of the feet characterized by clear, deep blisters that itch and burn. Cause are unknown. also known as vesicular palm plantar dermatitis, dyshidrosis, or pompholyx. occurs in up to 20% of people with hand eczema & common during the spring & summer months & in warmer climates.
Allergic rhinitis an IgE-mediated inflammation of the nasal mucosa in response to outdoor and indoor allergens affects between 10 to 30 percent adults and more than 40% of children worldwide Causes: pollens, dust mites, molds and insectso Symptoms: sneezing, runny or stuffy nose, teary eyes and itchy nose, throat or skin
Classification of Allergic Rhinitis Based on frequency & severity of symptoms mild intermittent mild persistent moderate/severe intermittent moderate/severe persistent Based on type of allergen perennial seasonal
Asthma life-long inflammatory disease characterized by airway hyper responsiveness & airflow obstruction the inner lining of the airways become inflamed and the muscles surrounding the airways tighten up mucus glands in the airways secrete thick mucus-cause the airway to narrow - leads to difficult breathing, shortness of breath, cough and wheezing Children with allergies have a 30% increased risk of developing asthma Genes play an important role in the susceptibility to develop asthma
Types of Asthma Allergic(Extrinsic) more common (90% of all cases) & typically develops in childhood. Approximately 80% of children with asthma also have documented allergies. there is a family history of allergies. Allergic asthma often goes into remission in early adulthood. However, in 75% of cases, the asthma reappears later.
Types of Asthma: Non allergic(Intrinsic) represents about 10% of all cases. develops after the age of 30 & is not typically associated with allergies. Women are more frequently involved , cases respiratory tract infection. The condition can be difficult to treat and symptoms are often chronic and year-round.
Asthma Exams, Tests & TreatmentExams and tests: lung (or pulmonary) function tests (spirometer, or peak flow meter) which measure lung function. Blood tests give a picture of your overall health; specific tests also measure levels of immunoglobulin E (IgE), a key antibody thats released during an allergic reaction. X-ray exam of you in order to visualize the structures inside your chest, including the heart, lungs, and bones.Treatment:bronchodilators/ inhalers
Anaphylaxis Anaphylaxis is the most severe allergic reaction and is potentially life threatening. Anaphylaxis is rare. The vast majority of people will never have an anaphylactic reaction. The most common causes of anaphylaxis include drugs, such as penicillin, insect stings, foods, X-ray dye, latex, and exercise. The symptoms of anaphylaxis may vary and can include hives, tongue swelling, vomiting, and even shock.
Allergy diagnosis Skin prick test Blood Test Patch test
Rush immunotherapy (RIT) very quick shots given every few hours, instead of every few days or weeks, to increase the tolerance to an allergen patients receiving both Omalizumab (monoclonal antibody) & RIT had fewer adverse symptoms than those receiving either treatment alone Pretreatment of Omalizumab enhances both the efficacy & the safety of Rush immunotherapy
Homeopathic remedies Lycopodium, Pulsatilla and sulfur can be useful in reducing allergic respons Intestinal commensal bacterial flora or eating the right kind of yoghurt can also be used for inhibiting the development of allergic responses to food related allergens
Avoiding exposure personal hygiene may be the best alternative for reducing allergies Persons prone to respiratory symptoms should avoid exposure to allergens; they should cover their noses or wear pollen/dust masks while going outside or exercising during pollen season Air purifiers and cleaning of air vents and duct scan help in cleansing the air. Avoid exposure to stored clothes in boxes or wardrobes for months after removal from storage and wash them before wearing to avoid the pets