Allergy World

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What is allergy ?

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An allergy is a commonly occurring, chronic condition involving an abnormal reaction to an ordinarily harmless protein substance called an allergen. Sometimes it can be genetic.

Allergies are increasing in India and affect around 30 crore Indians. There are many causes of allergy, and symptoms can vary from mild to potentially life threatening. Allergy is one of the major factors associated with the cause and persistence of asthma, rhinitis, atopic dermatitis & sinus disease.



Who Has
Allergies & why ?

In a patient suffering from allergy, the patient’s immune system views the allergen as an invader and a cascade reaction starts. White blood cells of the immune system produce IgE antibodies. These antibodies attach themselves to special cells called mast cells, causing a release of potent chemicals mediators such as histamine which cause the allergic symptoms.

Causes :

  •    allergies can be genetic; when a parent is allergic, the child has a 50% chance of developing allergy
  •    The hygiene hypothesis: An over-emphasis on cleanliness & a reduced incidence of bacterial and helminthic infection sin childhood may predispose to the development of allergy in later life.

The word allergen can be any substance that either enters or come into contact with the body, which is capable of producing allergies. Allergens can be found in food, drinks, or the environment.Allergens can also include aeroallergens such as dust mite, fungus, tree pollen, weed and grass pollen, as well as food allergens such as milk, egg, soy, wheat, nut or fish proteins.

People experience different symptoms, depending on the allergen and where it enters the body. Allergic reactions can involve many parts of the body at the same time. Usually allergy affects the respiratory system, the skin, the nose and sinuses, and even the gastro-intestinal system.

If an adult or child has excessive allergy symptoms, it is advisable to visit an allergist, who has advanced training and experience to determine what is causing your allergic symptoms and may be able to prescribe a treatment plan to help him/her feel better and enjoy a better quality of life.

Types of Allergies

Symptoms of Allergies

An allergic reaction causes inflammation and irritation. The signs and symptoms depend on the type of allergen. Allergic reactions may occur in the gastrointestinal system, skin, nose & sinuses, airways & eyes. Some symptoms allergens routinely cause in people who are allergic.

Some symptoms allergens routinely cause in people who are allergic.
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  •    Dust and pollen
    •   blocked nose
    •   itchy eyes and nose
    •   runny nose
    •   swollen and watery eyes
    •   cough/wheezing

  •    Skin reactions
    •   flaking
    •   itching
    •   peeling
    •   rashes

  •    Medication
    •   wheezing
    •   swollen tongue, lips, and face
    •   skin rash
    •   itchiness
    •   possible anaphylaxis
  •    Food
    •   vomiting
    •   swollen tongue
    •   tingling in the mouth
    •   swelling of the lips, face, and throat
    •   stomach cramps
    •   shortness of breath
    •   abdominal bloating
    •   itchiness in the mouth
    •   diarrhea

  •    Insect stings
    •   wheezing
    •   swelling at the site of the sting
    •   a sudden drop in blood pressure
    •   itchy skin
    •   shortness of breath
    •   restlessness
    •   hives, a red and very itchy rash that spreads across the body
    •   dizziness
    •   cough
    •   chest tightness
    •   possible anaphylaxis

Anaphylaxis

Anaphylaxis is a quickly escalating, serious allergic reaction that sets in rapidly. It can be life-threatening and must be treated as a medical emergency.

The traditional classification for hypersensitivity reactions is that of Gell and Coombs and is currently the most commonly known classification system. [1] It divides the hypersensitivity reactions into the following 4 types:

-- Type I reactions (ie, immediate hypersensitivity reactions) involve immunoglobulin E (IgE)–mediated release of histamine and other mediators from mast cells and basophils. [2] Examples include anaphylaxis and allergic rhino-conjunctivitis.

-- Type II reactions (ie, cytotoxic hypersensitivity reactions) involve immunoglobulin G or immunoglobulin M antibodies bound to cell surface antigens, with subsequent complement fixation. An example is drug-induced haemolytic anemia.

-- Type III reactions (ie, immune-complex reactions) involve circulating antigen-antibody immune complexes that deposit in post-capillary venules, with subsequent complement fixation. An example is serum sickness.

-- Type IV reactions (ie, delayed hypersensitivity reactions, cell-mediated immunity) are mediated by T cells rather than by antibodies. An example is contact dermatitis from poison ivy or nickel allergy.

Some authors believe this classification system may be too general and favor a more recent classification system proposed by Sell et al. This system divides immunopathologic responses into the following 7 categories :

  •    Inactivation/activation antibody reactions
  •    Cytotoxic or cytolytic antibody reactions
  •    Immune-complex reactions
  •    Allergic reactions
  •    T-cell cytotoxic reactions
  •    Delayed hypersensitivity reactions
  •    Granulomatous reactions

Allergy
Treatment

Effective treatment of allergic asthma includes identifying and avoiding allergens that trigger symptoms, using drug therapies and developing an emergency action plan for severe attacks.

  •     IDENTIFICATION – ALLERGY TESTING
  •     SYMPTOMATIC TREATMENT – TOPICAL SPRAYS AND            ANTIHISTAMINIC TABLETS
  •     AVOIDANCE OF ALLERGENS
  •     IMMUNOTHERAPY

Contact Dermatitis

(Its causes, symptoms and treatment)

Are You Allergic to Your Clothes ?

When certain physical or chemical agents come into direct contact with the skin, they might trigger an allergic reaction, causing the skin to become inflamed, red or itchy. This response is known as contact dermatitis.

There are two distinct types of contact dermatitis :

1] Irritant dermatitis :

This is a direct response of the skin cells to a causative agent. As soon as the skin is exposed to the irritant, the epidermal cells release mediators, which initiate and regulate skin inflammation. Although the intensity of the reaction depends heavily on the duration of exposure and the chemical components of the irritant, it is also influenced by existing skin conditions and disorders, and environmental factors such as humidity, temperature, etc.
Physical irritants include friction and grazing.
Chemical irritants include hand soaps, detergents, etc.

2] Allergic contact dermatitis :

When the skin is exposed repeatedly to an allergen, it gradually becomes sensitised to the allergen, leading to inflammation and irritation. The causative agent first penetrates the outermost layer of the skin, after which it merges with skin proteins, producing an immune response. The skin may take 5 to 21 days to grow sensitised to the allergen. Common causes of allergic contact dermatitis include chromium, neomycin, nickel, balsam of Peru and cobalt. Allergens are often also present in jewellery.

There are certain factors which predispose individuals to developing AECD:

  •    Genetic make-up, the consumption of certain drugs and certain existing diseases may make an individual more susceptible to AECD.
  •    If the patient’s skin is prone to irritation and inflammation, or is already diseased, he/she might be more prone to AECD.
  •    Occupation, environment and geographical location are responsible for the chemicals or substances that the individual is exposed to.
  •    Psychological factors such as stress may exacerbate symptoms of contact dermatitis. Certain hormonal imbalances may also encourage the development of dermatitis.

Occupational exposure :

You may be exposed to certain irritants at the workplace, which may either cause an immediate allergic reaction, or sensitise the skin over a period of time. Agricultural workers, factory employees, cooks, mechanics, healthcare workers, cleaners, etc. are constantly exposed to potential allergens and irritants. The hands are one of the most common sites for contact dermatitis. Common irritants include paints, solvents, oils and detergents, while metals, epoxy resins, rubber, etc. are potential allergens.

Allergies to medicines and medical equipment :

Some creams contain preservatives, such as propylene and butylene glycols; parabens; benzyl alcohol, sodium metabisulphate; lanolin, etc.
Topical corticosteroids can also trigger AECD.
Latex-based medical equipment such as gloves, catheters, intubation tubes, etc., when exposed to over a long period of time, may lead to the development of AECD.

Photocontact dermatitis :

Certain substances, either when consumed or applied directly to the skin, may become irritants (phototoxic) or allergens (photoallergenic) when exposed to sunlight.
Phototoxic dermatitis is an immediate response, and occurs when the substance becomes an irritant in the presence of sunlight. It mostly develops during or after the first exposure.
Photoallergenic dermatitis develops over a period of time. The skin (mostly of the face and the hands) experiences inflammation as a delayed response to exposure.
Possible topical agents include: detergents, bleaching powders, soaps, cosmetics and lotions, ointments and perfumes. Possible systemic agents include: antibiotics, anti-bacterial medications, diuretics and antifungal medications.

Symptoms :

Although the clinical presentation of contact dermatitis may vary depending on whether it is irritant or allergic in nature, common symptoms include redness, itching, rashes and inflammation. The skin may appear scaly, with well-defined borders.
A more detailed description of the symptoms is provided in the table below.

Category Irritant Contact Dermatitis Allergic Contact Dermatitis
Location Often the hands Areas that are relatively more exposed, eg. hands and face
Common symptoms Burning sensation, itchiness (pruritus), pain or discomfort Itchiness is the main symptom
External appearance Cracked, dry skin Fluid-filled sacs or blisters on the surface of the skin.
Demarcations Borders less apparent Well-defined borders.


Diagnosis

A full history of the patient’s occupation, pastimes and topical or systemic medication should ideally be taken into account when diagnosing contact dermatitis.
Patch testing is considered to be most effective. Patches contain small amounts of chemicals, metals, medicinal substances, rubber, dyes, and a variety of other additives to which the patient may potentially have developed an allergy. These substances are present in a diluted form. The patches are then applied to the patient’s back for 48-72 hours, where a localised allergic reaction may develop. This helps determine the causative agent.

Treatment

  •    Avoidance. It is recommended that soaps, fragrances and detergents be avoided completely, and the possibility of friction minimised. If the cause of contact dermatitis is occupational, the patient should ideally wear some form of protective equipment, such as gloves.
  •    Antihistamines may help soothe the itchiness. Hydroxyzine and cetirizine are highly recommended.
  •    Certain ointments, namely tacrolimus, help suppress calcineurin, a protein phosphate responsible for activating T-cells and causing a reaction.
  •    Emollients and palliatives rehydrate the skin by creating an oily coating on its surface, which helps trap moisture.
  •    Systemic steroids, which are only used for serious reactions.
  •    Inflammation can be reduced by administering high-potency topical corticosteroids. These, however, should not be applied to areas where the skin is particularly thin, as they put the epidermis and dermis at risk of degradation.

Ocular (Eye) allergies or Rhinoconjunctivitis

Ocular allergy is estimated to affect at least 20 percent of the population on an annual basis, especially amongst the younger age group, and the incidence is increasing.

Allergies may frequently trigger an itching sensation in the eyes. Often, this problem is compounded with rhinitis (sneezing/watering and nasal obstruction). This is because your immune system may not have the ability to tolerate, or properly react to, certain substances present in your immediate environment. These substances (called allergens) include, but are not limited to, dust, pollen, mould and cosmetics. When such allergens are present in your surroundings, they can affect your eyes’ mast cells, causing an itching sensation.

There are various kinds of allergies affecting the eyes, each of which shows varying symptoms.

   Seasonal Allergic Conjunctivitis (SAC)

This allergy is caused by the presence of pollen in the environment, and is most commonly experienced.
Symptoms: You may experience itching, redness, stinging, watery eyes or burning.

   Contact Allergic Conjunctivitis (CAC)

Another very common type of allergy, caused by the use of contact lenses.
Symptoms: You may experience itching, mucus secretion, redness and a general feeling of irritation in the eyes.

   Vernal keratoconjunctivitis

Mostly affecting males, this type of allergy involves a year-round itching sensation, exacerbated during certain seasons. It is a serious condition which, if ignored, may damage your vision.
Symptoms: Besides experiencing intense itching, you may feel as though you have a foreign object in your eyes. Eyes may also secrete mucus, produce a large volume of tears and be highly sensitive to light.
Older people may develop a similar form of this condition, known as atopic keratoconjunctivitis, which can result in corneal damage if left untreated.

Migraine

Headache: Is it related to allergy, migraine or is it a sinus headache?

Allergies are linked to two types of heada ches: sinus headaches and migraines . If you feel pressure in and around your nasal cavity, you or your doctor may assume you have a sinus headache. But you may have an allergy-induced migraine instead. A specialist ENT may be able to diagnose whether you are su ffering from either sinus headache or migraine. In some cases, managing your allergy symptoms may also help you control your migraines.

There are various kinds of allergies affecting the eyes, each of which shows varying symptoms.

Similarities between a sinus headache and migraine include:

  •    headache
  •    pressure in your sinuses
  •    nasal congestion
  •   watery eyes
  •   pain and pressure that worsens when bending forward

Differences between a sinus headache and migraine

There are also several differences between a sinus headache and a migraine: If you have the following:

  •    foul-smelling breath
  •    fever
  •    decreased sense of smell
  •   headache that lasts for many days but goes away after treatment
  •   pain in the upper teeth
  •   yellowish or greenish nasal discharge
  • You may be suffering from sinusitis

If, however you are suffering from:

  •    pain on one or both sides of head (temples)
  •    throbbing sensation
  •    sensitivity to light
  •   nausea and vomiting
  •   nasal discharge that’s clear
  •   a headache that lasts hours or up to three days and you feel better after resting in a cool dark area
  •   visual disturbances/haloes
  • then it is more likely to be a migraine headache

Can allergies trigger a migraine ?

Allergy sufferer s are 10 times more likely than others to develop migraines.
One study found that people with allergies experience a higher frequency of mi graines than those who do not have allergies.
In fact the majority of people who appear to have a sinus headache without inflammatory symptoms and a normal sinus CT scan in fact have a migraine. There is no known reason why allergies and migraines are linked except that certain internal and external triggers release histamine in both conditions

How best to treat a n allergy-related migraine ?

Factor in both your allergies and your migraines when seeking treatment.

Controlling allergies should be your first line of treatment. Your doctor can perform allergy tests to determine what you ’ re allergic to and how to treat it.

The first line of treatment is to use antihistaminic and steroid nasal sprays. if, however, the allergic symptoms are frequent, you may need allergy diagnosis & immunotherapy and nasal sprays. Antibiotics may be needed if your symptoms are from a sinus headache.

Simultaneously the migraines should be managed , either by treating the symptoms as they occur with medications like nonsteroidal anti-inflammatory drugs or, if the migraines are repeated and severe, other medications can prevent the onset of a migraine, including antidepressants, beta-blockers, and calcium channel blockers. Along with the medications, your doctor may prescribe a migraine-prevention diet for you.

Ensure that all treatment is taken under competent medical supervision, as medicines may have side effects.

Treatments

   Immunotherapy

The only treatment that will continue to benefit the patient after the completion of the course. Immunotherapy suppresses the Th2 response and promotes T-cells, thus strengthening the body’s ability to tolerate the allergen. Two of the most common kinds of immunotherapy for ocular allergies are:

  • 1] Subcutaneous Immunotherapy: Aims to treat allergies caused by environmental allergens such as pollen and grass. Treatments are available as pre-seasonal and year-round injections, and should continue over 3 to 5 years to ensure steady recovery.
  • 2] Sublingual Immunotherapy: Available in the form of a solution, or soluble tablet. Clinical trials have shown a significant reduction in symptoms such as redness, itchiness and swelling. 

   Antihistamines

  • 1] Oral antihistamines: These are available over the counter or by prescription, and are very commonly used to treat allergies.
  • 2] Topical antihistamines: These are more effective than oral antihistamines, as they are applied directly to the eyes, and are therefore not absorbed systemically. They usually take effect 3 to 15 minutes after application. 

   Mast cell stabilisers

Cromolyn Sodium  or Nedocromil sodium. During an allergic reaction, the antibody IgE, which is present on the surface of mast cells, attaches itself to proteins present in the allergen. This often leads to problems like congestion. Mast cell stabilisers can prevent this process when administered as prophylactics before the onset of an allergic reaction.

   Topical dual-activity agents

This treatment combines mast cell stabilisers and antihistamines. The antihistamines help in relieving the symptoms of the allergy, while the stabilisers work towards preventing allergic reactions in the future.

   Topical, ophthalmic and nasal steroids

Steroids are effective immediate treatments that help mitigate immune responses to allergens. Long-term consumption, however, may result in problems such as cataract formation.
Ophthalmic steroids are very often combined with dual-activity agents, when the symptoms grow more noticeable. They may even be used when the patient is expected to be exposed to allergens, in order to prevent an allergic reaction.
Topical ketone-based steroids are very strong, and are only needed to treat severe allergic reactions. They are not used very often due to the possibility of deteriorative side effects on the eyes.
Nasal steroids, commonly used to treat allergic rhinitis, can also reduce the effects of an ocular allergic reaction.