Dr. Rajiv Path Lab with your co-operation is constantly evolving and innovating diagnostic organization dedicated to setting and meeting exacting needs of laboratory diagnostics, for the immunodiagnosis of thyroid and fertility hormones, cancer markers, diabetes marker, infectious diseases assay, autoimmune diseases, HLA markers, Hba1c microalbumin, CRP, lipid testing, basic clinical chemistry panel, allergy diagnostics and clinical pathology,electrophoresis, Cardio-pathological and imaging(radiodiagnosis)
which are managed by qualified and deserving professionals, un-interfering & independent faculties.
The aforesaid objectives can only be achieved through:
The application of state –of –the- art technologies to the services that we make available.
Interfacing with our esteemed doctors on the technical and procedural aspects of the techniques required by them.
We are indeed glad to launch an additional wing to add up to the services provided to you.
What is Allergy ?
An allergy is an abonormal reaction or increased sensitivity to certain substances. It is the collective name given to a wide spectrum of clinical conditions. They are all caused by overproduction of an antibody (a special protein) called immunoglobulin E (or lgE) by the body’s immune system.
“ Up to 30% of all visits to General Practitioners or Paediatric Specialists are because of allergy.”
It is becoming more common because of increasing urbanization and changes in diet and lifestyle. It is important to use the term” allergy” correctly. It is incorrect to use it where lgE is not involved. This is especially true for so-called”food allergy.”
Substances that cause allergies are called “allergens” Over 700 environmental allergens have been identified, characterized and purified. These are important for a modern approach to diagnosis nand treatment of allergies. Differentiation must be made between different allergens whose amino acid sequience has been completely established.
Facilitating allergy assessment, diagnosis and a long lasting patient relief.
Treat your allergy patients by further counseling and your follow up whenever needed.
Quick, easy access to the latest allergen information and peer-reviewed notes with every report.
Keeping yourself informed and educating your patient at your clinic once the report reaches you the same day.
Gives you an additional wing of “treatment based allergy care” at your clinic.
TARGET BASED APPROACH NEEDED FOR MAXIMUM RESULT ORIENTATION WITH MINIMUM PATIENT DISCOMFORT.
Q: IS IT ALLERGY?
Is it allergy?
Eczema 1 out of 3 infants and young children with eczema has underlying allergy and may benefit from a diet or other form of avoidance - which ones are they? Persistent symptoms should always be tested.
Rhinitis Up to 7 out of 10 children and many adults with seasonal and perennial rhinitis are allergic and may benefit from differential diagnosis and treatment.
Wheeze/Asthma 1 out of 3 preschool children and 2 out of 3 school children with recurrent wheezing/coughing are allergic and may benefit from allergy screen and treatment.
Similar figures are also applicable to adults .
Atopy : Genetic ;predisposition to develop allergic (Type 1)Disease
Sensitization : activation of the immune system with development of allergen specific lgE antibodies.
Allergy : clinical manifestation of an allergic disease as a result of allergic sensitization.
Allergic reactions or diseases may involve any part of the body: the most frequently involved are the nose and chest with resultant symptoms of hay fever rhinitis or asthma, respectively. The skin and deyes also commonly show allergic symptoms. Anaphylactic shock is a severe allergy, which affects many organs at the same time causing a rapid decrease in blood pressure, fainting and, occasionally, death. Such a reaction, though, is rare.
The pollens of grasses, weeds and trees are the main causes of this type of allergy, although mold spores can also cause the symptoms. The lining of the nose becomes swollen and exudes a runny discharge. Spells of sneezing and itchiness of the throat and palate a;so occur and the eyes may be similarly affected. Depending on location and the pollinating periods, attacks may occur in spring, summer or autumn.
Perennial Allergic Rhinitis
The symptoms are similar to hay fever but appear all the year round . This condition is caused by non seasonal allergens such as house dust components and certain molds.
EYE ALLERGY (CONJUNCTIVITIS)
Allergic conjunctivitis is often associated with allergic rhinitis. A general complaint is of itchiness of the eyes, which are rubbed frequently.
?ASTHMA OR ALLERGY
The asthmatic attacks obstruct the flow of air to the lungs. Breathing becomes diffcult and forced breathing becomes necessary. A wheezing sound can appear, due to the rush of air through the narrowed airways. At the same time, a troublesome cough can develop. Asthma may begin at any age and, if neglected, tends to recur and become chronic.
The skin can become irritated and develop rashes that can be either wet or dry. The reactions are often accompanied by severe itching. The cause is often not clear, but is frequently seen in children of families with a history of allergic diseases. The eczema may start during the first year of life, on the face. Later, it is often seen on the inside of the elbows and backs of knees, on the neck, ankles, wrists and on the back of the hands. It is possible for eczema to become secondarily infected with skin bacteria, especially if there is much broken skin due to scratching.
Urticaria, Hives (Neetle rash)
This reaction appears very suddenly. The skin becomes warm, reddish and itching. The symptoms may last either for a couple of hours or up to a whole day. Blotches may appear as raised wheals and vary in size from smaller than a mosquito bite to several inches in diameter.
In 95% of hives, the cause is unknown.
The symptoms of contact dermatitis is similar to Hives, but this reaction is of another type. The cause is direct contact with different substances, such as:
Nickel (in coins, stainless steel, clasps, jewelry)
Rubber products(in gloves, boots, waistbands)
Chromium (in cement, leather)
Preservatives(in creams, ointments and cosmetics)
This condition, unlike those listed above, is not due to the production of lgE antibodies, but is due to a different kind of immune reaction. It is usually due to increased sensitivity to a substance that a particular body part contacts.
Food allergy means that body reacts to certain foods. It is also called food hypersensitivity. Common symptoms are itching and burning around the mouth, asthma and vomiting. About 90 per cent of allergies are caused by nuts, eggs, milk or soy. Food allergies are on the increase in our region and in India as a whole.
Food allergy causes the body to mount an immune response against the food. Symptoms include:
Breathing difficulties, including wheezing and asthma
Itching, burning and swelling around the mouth
Nausea, vomiting, abdominal cramps and diarrhea or costipation
Generalised urticaria - skin becomes red and raised,hives.
About 90 per cent of allergies are caused by nuts, eggs, milk or soy. Food allergies are on the increase in our region and in India as a whole.
Food allergy causes the body to mount an immune response against the food. Symptoms include:
Severe allergic reactions to bee and wasp stings are not uncommon. The local toxoc reaction and discomfort that usually occurs following an insect sting is not generally considered to be allergic. lgE mediated(allergic) reactions induce symptoms such as nettlerash (urticaria, hives), running nose and eyes, swelling of the throat, attacks of asthma and, in severe cases, fainting.
The term occupational allergy is generally used to describe episodes of allergic reactions occurring after working with industrial dusts, vapors, gases of fumes, furthermore, substances like nickel (in coins), chromium (in cement), rubber, different dyes, formaldehyde and glues may result in eczema that occurs at the site of contact with the skin. Inhalants such as grain dust may affect farmers. The degree of eczema depends on the length of exposure and sensitivity to the substance. Symptoms may show within some weeks but it can often take months, years and sometimes decades before an eczema develops. Any part of the skin may become affected. but the most frequent sites are the hands, arms and the face, because these tend to be the least protected parts of the body. Occupational allergy may also present with pulmonary or upper respiratory treatments. Workers often get better over the weekend, on business trips, or vacation and symptoms recur after returning to the same work environment.
Role of Allergy in Various Diseases
Who Becomes Allergic?
Anyone can develop an allergy, but the probability is increased if one or both parents suffer form some kind of allergic condition. Indeed, the presence of another allergic individual in the family is the strongest factor for predicting allergy in a child may not be. Conversely, allergic children are born to normal parents and in such cases other factors, such as infection, may be responsible for the development of the allergy. Repeated exposure to a substance is required before the body can recognize it as foreign and mount an allergic response.
The steps in lgE mediated allergy are:
Initial exposure to allergen leads to production of allergen specific lge. antigen presenting cells (dentritic cells) recognize and process the antigen and presents it to tlymphocytes stimulating of cytgokines. direct interaction of t and b cells stimulates antigen specific lge production by b cells which binds with fc receptor on mast cells and or basophills.
Early phase Reaction (Immediate Hypersensitivity)
it occurs within minutes of subsequent exposure of the lge antibody to the allergen. the allergen crosslinks the surface bound lge and stimulates the release of histamine upon reexposure of the same allergen mast cells (and basophills) degranuate releasing histamines tryptase and heparin along with newly synthesized mediators like leukotrience and cytokines.
Late phase Reaction
Allergen also stimulate immune cells (mast cells,Tcells) to produce inflammatory mediators (leukotriness,cytokines).These mediators act as post – capillary endothelial cell, promoting :
. outflow of plasma leading to localized edema.
. Adhesion of circulating leukocytes.
. Infilltration of tisues by eosinophils,neutrophills and basophills.
over the course of several hours, the infiltrating inflammatory cells become activated and release mediators stimulating and enhancing further inflammatory response.
Type 1 IgE ReceptorsType 2 lgE ReceptorsTaget CellsMast Cells, BasophilsLymphocptes, Platelets, Eosinophils, Monocytes & MacrophagesAntibody Affinity for IgEHigh Affiinity for IgELow Affinity for IgEMediatorsHistamine, ECF-A, Leukotrienes, Bradykinins, Prostaglandins, PAF, anaphylatoxinsChemotactic Factors, IgE Binding Factors, Mitogens, inflammatory Mediators
IgE is a homocytotrophic antibody – an antibody capable of interacting with target cells such that these cells release mediators on contact with specific antigen. There are two categories of lgE receptors depending upon the type of cells targeted, antibody affinity and the type of mediators released.
Why lgE and Not lgG?
Acute allergic reactions result from the release of preformed granule associated mediators, deprived lipids, cytokines and chemokines when an allergen interacts with lgE that is bound to mast cells or basophils ny the chain of high affinity lgE receptor. This receptor also occurs on antigen presenting cells, where it can facilitate the lgE dependent trapping and presentation ofr allergens to T cells, Eosinophils also process high affintity lgE receptor, but in these cells it is almost entirely intracellular; after being released by degranulation of the eosinophil, it may help regulate local levels of lgE.
The most important inducers of the production of lgE are inerleukin-4 and interleukin-13 these cytokines initiate transcription of the gene for the epsilon class of the constant region of the immunoglobulin (lg) heavy chain. The production of lgE also requires two transcription factors, nuclear factor-B and stat-6 the former pathway involves the co-stimulatory molecules CD40 and the CD4 ligand(CD154) and the latter is activated when interleukin-4 binds to the high affinity alpha chain of the interleukin-4 receptor.
Who Should be tested for allergy ?
Generally, all individuals with severe, persisting or recurrent possible allergic symptoms and individuals with need for continuous prophylactic treatment should be tested for specific allergy irrespective of the age. The extent of allergy tests will typically depend on the age. The extent of allergy tests will typically depend on the age, positive family history, and the character of the symptomatology including possible seasonal or diurnal variations. When children are tested according to age for specific allergy diagnosis, additional testing might be considered for assessment of sensitization reflecting the atopic constitution. The accurate identification of the cause(s) of allergic symptoms is a cornerstone of management.
Evaluation of the patient”s environment
Evaluation of the patient”s immunological responses to allergens.
It is essential for successful treatment that the allergens responsible for the symptoms are accurately identified. There are different ways to arrive at a diagnosis. The case history is extremely important in all allergy investigations. Based on what the patient tells about his/her symptoms, the doctor decides what tests, if any, should be carried out.
The case history should form the basis for all allergy investigations in order to give the doctor an idea of the mechanisms and allergens causing the trouble, the doctor will question the patient or ask him/her to fill in a questionnaire. It is important to know when and how the symptoms developed. Also important if the relationship to seasons, damp weather, physical activity, certain foods, etc. Knowledge of personal habits such as smoking, occupation, hobbies etc, will be necessary and some information about the home can be important( e.g. whether there are pets, or fitted carpets in the house or if cleaning aggravates symptoms) A favorite cologne or perfume can be the cause of allergic conjunctivitis, while a soap may be the cause of chronic eczema. Finger polish may cause eczema. In nasal , the case history alone may give enough information to settle the diagnosis and the doctor can then decide which measures to take to help the patient. In more complicated cases, however, further investigations may be performed to get a final diagnosis.
There are several methods of skin testing. The most significant skin tests are those which correlate with the patient’s history(i.e, a positive shin test for ragweed is not significant if ragweed never causes allergy symptoms) drops of the suspected a;;ergens are put on the skin of the forearm and the skin is either pricked or scratched (prick or scratch test) through the drops. Suspected allergens can also be injected into the skin of the back ( intradermal skin test) After 15-20 minutes, if there is an allergy to one or more of the substances, a round wheal with a flare forms on the spots where the substances were injected . This may identify and confirm the allergy . However, desides causing the patient some trouble , the intradermal skin tests may not be very reliable . Drug treatment for the allergic symptoms in the 72 hours prior to the skin test may invalidate the results, and skin testing in small children is both inconvenient and unreliable.
Patch testing is used in the investigation of allergic contact dermatitis. The test in performed by using a small piece of blotting paper, moistened with the suspected substance, or a prepared strip containing various standard allergens. The raper of strip is taped to an area of healthy skin for 24 or 48 hours. If the patient is allergic to the substance tested, eczems eill be seen where the test substance has been in contact with the skin.
Provocation and Elimination Tests
These tests are performed in the eyes and nose inh hay fever sufferers. A highly diluted allergen extract is dropped into the nose or eyes or is inhaled . The continued in this way using more concentrated allergens until the allergic symptoms are provoked. This shows that the tested allergen is responsible for the patients symptoms. When allergy tl food is suspected, different foods ( usually those most commonly associated with allergy) are eliminated to see if the symptoms disappear. They are re introduced into the diet, one by one, to see if any of them causes a return to the symptoms. The most common food sensitivities are to cow”s milk, corn, wheat, eggs and soy. The skin and provocation tests, apart from being inconvenient to the patient, have other disadvantages.
In-Vitro allergy Testing
Because of the limitations and disadvantages associated with skin and provocation tests, there has been a need for more convenient and reliable methods. Today, there are laboratory tests available that accurately measure lgE, and a small blood sample is sufficient for allergy testing. These tests measure either the total amount of lgE in the blood, which indicates if your symptoms are of allergic origin or specific lgE, which tells the doctor which are causing the trouble.
Total lgE Test
This measures the total amount of lgE in the patient’s blood. This is compared to normal levels for the age and race. The level gives an indication of the patient’s degree of sensitisation to all allergens. Araised level shows that the patient is probably allergic.
Allergen Specific lgE Tests
Often the doctor will be certain that the patient is suffering from an allergy and suspects a particular individual allergen. If this is the case, further testing with one or more specific lgE tests can confirm or identify the allergen(s) involved.
To interpret the results of allergen specific lgE testing, the following factors must be taken into consideration:
Besides allergen characterization, allergen standardization is increasingly important. This is bcoming more significant particularly because of the need for quality assurance which is an integral part of the diagnosis and treatment of allergy. It is critical that for every allergen the highest purity should be used in diagnostic tests. In order to ensure comparability between different lots, allergen quantification methods must adhere to international allergen standards. The clinical specificity of the tests is directly depending on the origin of the allergen extract in use. Their purity and their quantification.
The calibrator should be traceable to WHO standard reference preparation must be used in the assays for quantification of specific lgE antibodies
The analytical sensitivity of the lgE antibody test is determined in part by the labeled anti lgE antibody used in the second stage of the assay. Commercial labeled, affinity purified anti lgE antibodies function well as detection proteins ad enable the measurement of nanogram quantities of specific lgE antibodies.
Allergic cross reactions exist between many foods sand other products. In beef allergy cross reactivity may be present with all other cow’s milk products and veal. In seafood allergies involving fresh and saltwater fish, shelfish and crustaceans, many cross reactions exist.
Cross reactions Between Allergens of Animal Food Orgin
The detection of allergen specific IgE antibodies does not necessarily correlate with positive skin test reactions. Mast cell bound IgE has a considerable longer half life (month to years) than serum IgE (2-3 days). A positive skin test in patients with pollen allergy is still detectable after the end of pollen season whereas IgE antibody may decline rapidly.
The specific IgE antibody level may not correlate with the sverity of symptoms and the clinical presentation. Higher levels of allergen specific IgE antibodies are found in severe atopic dermatitis and in p[atients with severe allergic reactions not undergoing adequate treatment.
A decline in specific IgE antibody levels during therapu, including desensitization treatment does not necessarily occur. Also, a decline in specific IgE antibodies does not confirm the success of therapy.
A number of factors including lifestyle and living conditions have an impact on the IgE levels. Active and passive smoking may result in increased IgE.
In-Vitro IgE Testing Advantages
Laboratory tests for IgE plays an important role in allergic rhinitis, allergic asthma and in some forms of eczema. Detecting and accurately measuring the amount of IgE may be of great importance when diagnosing allergies.
Laboratory tests are accurate and convenient and can be used for a broader range of allergens than skin tests can. They are also more suitable for babies and patients with eczema in whom it is difficult to do skin tests. Laboratory tests are not affected by symptoms or by treatment. As a results of dramatic developments in diagnostic medical technology in recent years, coupled with the increasing knowledge and understanding of allergic processes by medical researchers and doctors, it is possible to identify the cause of an allergy in over 95% of cases if skin tests and laboratory tests are used. The doctor can choose which tests will suit the individual patient and the individual circumstances. It is important that the results of the tests are carefully interpreted by a doctor who has training in and therefore a good understanding of allergy. Only then can the best treatment and patient management be carried out. Better diagnosis can then be coupled with the recent developments in chemotherapeutics, with new classes and new formulations of drugs, leading to greatly improved management of the allergic patient.
When To Ask For IgE Tests
Serum IgE tests can be generally recommended in :
Diagnosis of IgE myeloma
Extended investigation of allergies parallel to screening for specific IgE antibodies as part of differential evaluation of diseases with a possible allergic component.
Extended investigation of allergies in case of eosinophilic pulmonary infiltrations, allergic aspergilosis, allergic alveolitis.
Lllness associated with eosinophilia or fever of unknown origin (drung related fever)
Suspected presence of parasitic diseases in case of blood eosinophilia of unknown origin with unsuccessful parasite detection.