Dr Sreekanth

Allergy Information

What is Allergy?

Allergy is an abnormal reaction to a particle which enters the body from the environment either by inhalation ( breathing), ingestion( eating), injection – (by bites of insects or by injection) and or by contact - the substance comes in contact on the surface of the skin or the mucous membrane of the body of person with allergy, which is usually harmless to other persons. whenever such substance enter the body, body recognizes the sensitive substance and a series of reactions happen either with in few seconds or in minutes to develop the various allergic manifestations

Why should we consider allergies seriously and start treatment at the earliest?

  • Allergic diseases if not treated properly by a trained allergy specialist can progress e.g; if allergic rhinitis is not controlled, asthma can develop later.
  • Repeated cough,repeated sinus, ear and chest infections.patient will be forced to take antibiotics almost once in every 2 wks.
  • Night cough interfering with sleep and thereby causing day time fatigue, sleepiness, poor concentration, road traffic accidents, absent from school and work etc…
  • Exercise induced asthma can develop there by resulting in inability to take part in sports which may inturn induce depression , especially in children
  • Poor weight gain due to recurrent infections in paediatric age group
  • Growth retardation -final height of the child is affected.
  • Psychological problem may occur especially due to itching of skin in public in children with skin allergies
  • Recurrent hospitalizations causing a huge economic burden in the family
  • Causes poor quality of life

What are the diseases known to be allergic in nature?

The common allergic diseases are :

  • Allergic rhinitis - sneezing, watery eyes and nose, post - nasal drip, nose block, congestion.
  • Allergic conjunctivitis - itchy, red watery eyes.
  • Allergic bronchial asthma - cough, wheeze, breathlessness and tightness of chest.
  • Atopic dermatitis - itching, reddening and feeling of flaking of the skin.
  • Allergic rhino - sinusitis - headache, congestion, throbbing pain in and around the eyes & cheeks, nose block, and post-nasal drip etc.
  • Urticaria & angioedma - itchy hives and non-itchy swelling of lips, eyes etc.
  • Anaphylaxis - a violent allergic reaction to insect stings, food, drugs and latex.
  • Food allergy – can induce recurrent urticaria, laryngioedma, atopic dermatitis, anaphylaxis etc e.g. peanut, fish, etc.
  • A.B.C.D. (air-borne contact dermatitis)
  • Contact allergy (chemicals etc)
  • A.B.P.A. (allergic - bronchopulmonary - aspergillosis)

what is allergic march or atopic march

The term allergic march or atopic march refers to progression or development of various allergic conditions with age. the tendency to have an allergic condition known as atopy makes one prone to develop other allergic conditions.

It is also noted that after certain age the allergy dissolves and becomes normal and recur after few years, which is commonly seen in most of the atopic children

Doctors and scientists are continually doing research for better understanding of allergy march.

What are the symptoms of severe allergy?

  • difficulty in breathing
  • wheezing or whistling sound from chest due to bronchospasm
  • fall in blood pressure
  • pain or tightness in the chest
  • heaviness of chest
  • palpitation(increased heart beat)
  • swelling of face, eyes or tongue
  • flushing and redness of face
  • dizziness and disorientation
  • nausea and vomiting
  • abdominal pain
  • diarrhoea

in case, patient is experiencing any of the above symptom/symptoms, the patient is advised to take emergeny medical help prefferably in an emergency room of a hospital itself at the earlest

Who can get allergy? why does one become allergic?

The causes of allergy are genetic predisposition, environment triggers and life styles. the genetic background plays a major role. It is commonly accepted that a if both parents are allergic the risk of developing allergy can be as high as 90%, if the father is allergic(but not the mother) the risk is upto 40%, where as if the mother is allergic(not father) the risk is upto 50% please also note that if parents are not at all allergic then also there is a 20% chance for getting allergy

Tenvironmental triggers play an important role. exposure to some type of pollens, fungus, dusts, insects, pets, some foods can trigger an allergy attack The exact life style for the cause of increasing allergic diseases is yet not identified, but most researchers agree that a close relationship with “westernisation of lifestyle”, one that results in a decreased bacterial load(eg. altered commensal flora) in young children may be one of the factors summarized as hygiene hypothesis

What can happen if allergic symptoms are ignored?

Our airway has multiple number ofmucous glands, which secrete mucus. This acts as a cleaning agent and traps dirt and other matter, which get wiped away by the beating movement of tiny hair like structures called the cilia. It is a natural process which occurs in the body to clean the airway by eliminating dirt and particulate matter(mucociliary escalator) these delicate tissues line the entire nasal cavity and the lung passages. Uncontolled allergic diseases over the years, can damage this natural mechanism , when the cilia and the mucus blanket are damaged, the mucociliary escalator is impaired the lung and sinuses, which cannot clean themselves, become clogged with thick diseased material and do not function normally.

Recurrent allergic symptoms may cause airway remodelling(smooth muscle hypertrophy, collagen deposition,hypertrophy of mucous glands,infiltration of inflammatory cells), which inturn decrease the internal diameter of the airways leading to more severe allergy symptoms as time progresses.

What allergy test is available to confirm the sensitized allergen?

Skin prick test (spt) for common inhalant and food allergens is currently the best sensitive and reproducible test available at affordable cost. First performed by Dr.Charles blackley in 1865 to identify grass pollen sensitivity in hay fever. This test is an invivo test which is more specific than blood tests

Skin prick test is an extremely safe test in expert hands. The test is not at all painful and can be done very safely in childrens also.

What about checking total serum ige? Does it really help?

Serum total ige have limited values as it can be elevated in non allergic conditions also.(like parasitic infestations,sle, rheumatoid arthritis,psoriasis,churg strauss syndrome, poly arteritis nodosa etc)

Estimating specific serum ige may be helpful, but is more costly(almost more than 10 times) and less specific than a skin test.

How to get prepared for allergy testing?

  • Allergy test is done preferrably when patient is free from symptoms.
  • Avoid all oral antihistaminics 5 days prior to allergy testing.
  • Remove hair from forearm flexor aspect with a trimmer if necessary.( please don’t shave as shaving can increase the sensitivity of skin and give false positive results)
  • Avoid tranquilizers ,cimetidine and ranitidine 1 week prior to test.
  • Longacting antihistaminics to be avoided 1 month prior to test.
  • Shortacting antihistaminics to be avoided 3 days prior to test.
  • Bronchodilators, adrenaline and steroids do not affect the sensitivity of skin test with allergen extract , hence a gap of 12 hrs is sufficient.
  • Patient is not permitted to use steroid creams or any other topical application drugs for allergy at the site of allergy testing.
  • Oral steroids to be stopped 2 days prior to testing.
  • Patient can continue inhaled medication and nasal sprays.
  • Antigens are administered in the volar aspect of the arm or on the back of the patient and reading is taken after 20 min.

What are the dangers of using corticosteroids for a long time?

Corticosteroids are present in our own body in significant amounts, and help maintain many important functions of the body. If corticosteroids are taken orally for a long time, this can derange the body’s own production of steroids, and can cause problems. These problems are of course, reversible to a large extent. However, in allergy, inhaled steroids are used. These work directly on the air passage (target therapy).The dose is almost 1/1000 that present in a tablet. Since the inhaled steroids are used in such low doses that they do not get into the blood stream, they usually do not cause any side effects but wrong inhaler techniques and oral deposition can create problems.

Followup with the treating allergy specialist in regular intervals , while using the inhaled drugs is very essential.

What are the side effects of long term use of steroids as tablets or injection?

Almost all adverse effects of steroids can develop including:

Diabetes mellitus, Hypertension, Osteoporosis, Immunosuppression, Striae on skin, Cushings habitus, Peptic ulcers, Delayed wound healing, recurrent infections, cataract, Raised pressure inside the eyeball, HPA axis suppression, Steroid induced psychosis etc..