Allergy is a reaction of the human defense system
against substances which do not commonly cause troubles, and which are
normally tolerated by most of the people. When a virus or a bacteria
enters the body, this produces defense ANTIBODIES, which destroy the
invading agent. In the case of allergy, something similar happens, but
antibodies are produced against a normally harmless (pollen, food, …)
substance, which is called allergen.
The reaction ALLERGEN-ANTIBODY is responsible for
symptoms, which depend on the part of the body where this reaction takes
place (coughing, wheezing, sneezing, hives, …) But these symptoms will
not appear until the level of antibodies (and hence, the severity of the
reaction) exceeds the individual level of tolerance.
Most of allergic people are allergic to several
Allergic diseases are responsible of a large number of medical and
labor problems. These diseases use to begin in childhood (although they
often do not appear until later in life).
Food allergy is the most frequent allergy in
infants and small children, and they predict the development of
allergy to inhaled substances in later life; that is, an infant with
allergy to food will very often develop allergy to inhaled allergens
when growing to an older age. Likewise, infants who present some
diseases at early age (like atopic dermatitis) will often present
other allergic diseases when growing (like asthma).
Nearly every substance is able to induce allergy in predisposed
The following links lead to specific pages on the different types of
INDOOR ALLERGY (mites)
OUTDOOS ALLERGY (pollen, molds)
ALLERGY TO PETS
If your or your child is allergic to one allergen, will
probably be allergic to more than one. Nevertheless, you must know that
the presence of symptoms depends on the exposure to an amount of allergen
able to exceed the tolerance of each patient. For instance, if a patient
is allergic to grass pollen, to mites and to dogs, and the recommendations
to avoid mites and pollens, this may be enough to remain most of the time
below the exposure threshold for presenting symptoms. Therefore, the fact
that someone has no apparent symptoms even when having a dog at home does
not mean that the patient is not allergic to dogs. It just means that the
whole allergenic load is usually below the tolerance threshold; but this
may be only transient.
Any case, we must remind that until the patient has not
been studied, we can't know if someone is really allergic, and to what
We come in contact with allergens through the air we
breathe, the food we eat, and things we touch. This means that allergic
reactions may appear in any part of our body. The most frequent symptoms
of allergy are the following:
Sneezing, often with nose obstruction.
Itching of eyes, nose, palate, ears or throat.
"Allergic salute" (upwards rubbing of
nose, which often gives place to a horizontal groove on the nose).
Conjunctivitis (red eyes, eye discharge,...).
Wheezing, breathing difficulty, chest tightness.
Skin rashes, hives, itching.
Stomach pain or cramps, diarrhea, vomiting (mainly
in infants and small children).
Allergy is often more severe than commonly thought. It
can affect to a great extent the quality of life of patients. But, even
more, allergy can cause or enhance the development of other associated
diseases. Consciousness is the key: when someone knows he is allergic and
to what allergens, the difference about how to treat and manage allergy
and its consequences can be noteworthy.
Otitis (inflammation of the ear) are a cause of frequent visits to the
pediatrician, and they are responsible for the highest percentage of
causes of hearing loss in children. Recent studies suggest that food
allergy may be responsible for repeated episodes of otitis in infants and
Asthma is the most frequent chronic disease in childhood, and it
affects about 10% of children. The symptoms of asthma are due to bronchial
inflammation, which is caused by allergy to house dust mites, pets, molds,
pollen, and so on. Identifying and avoiding these allergens will improve
Skin rashes, such as eczema, are very common in infants. They often appear
in the first months of life, and they may be caused by allergy to food,
like milk or egg. But, furthermore, eczema in a small child must alert
about the development of allergy on the long term. About half of the
children with eczema will have asthma in the future. Again identifying and
controlling the involved allergens will again be the key.
Rhinitis is an inflammation of the inner layers of the nose, which causes
sneezing, itching, obstruction. As with previous diseases, it is essential
to find out if it is of allergic nature, and which allergens are involved.
Nasal and paranasal sinuses are cavities in the skull bones, communicated
with the nose through small holes. These can be obstructed by inflammation
of the inner layers of the nose, giving rise to sinusitis. Sinusitis
(inflammation of sinus) would thus be caused by rhinitis, and the proper
treatment of the latter would resolve the former.
The allergologic study on the possible causes must be
performed as soon as the first symptoms suspicious of allergy appear.
Newborns rarely present symptoms of allergy. But when milk is started on
the diet, some children may present vomiting, diarrhea, infantile colics.
Sometimes, when this seems to vanish, skin symptoms (diaper rash, eczema,…)
will appear. Later on, "chest colds" or asthma, and finally,
allergic symptoms of the nose (rhinitis) or eyes (conjunctivitis) will be
As shown, there is a pattern for the development of
allergic diseases: people with allergic predisposition often follow the
same clinical course, with changes according to age. This is known as the ALLERGY
Hence, finding the cause as early as possible will help stop progression
of this march.
Factors contributing to
development of allergy.
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The Atopic Condition. Some people have a
genetic predisposition to develop allergic diseases. This
predisposition is inheritable. It is more probable that a child is
allergic, when other members of the family (mother, father,
siblings) are allergic.
Gender. Some allergic diseases (asthma) are
more frequent in boys than in girls.
Causal factors è
Coadjuvating and Triggering Factors: These factors
do not cause allergy by themselves, but they facilitate that someone
becomes allergic to factors described above, or they can trigger
symptoms in an already allergic person:
When your child has any symptoms, you want them to
disappear as son as possible. Certainly, itching, conjunctivitis, sneezing
or nasal obstruction are not life threatening, but they can become a whole
nuisance, and limit the quality of life to a great extent. Again, first of
all, to solve this problem, we must find the cause. We must be aware that
symptoms of allergic diseases are identical to symptoms of other non
allergic diseases. If you think your child is allergic, you must visit the
pediatrician, who, after a detailed clinical history and physical
examination, will decide if there is a basis for this suspicion. In this
case, the pediatrician will ask for a Allergy specialist to perform the
test which will confirm or discard the diagnosis.
There are two types of tests to find out if a child is
Skin prick tests è
The skin is punctured with a small lancet through a drop of the
suspect allergen. A minute amount of allergen gets into the skin, to
see if a reaction occurs. After 15-20 minutes, the presence of a wheal
lets know which allergens the patient is sensitized to.
Blood tests è
They are complementary to skin tests. They allow to confirm and to
quantify the degree of sensitization. A sample of 2-3 cc of blood is
enough to study sensitization to a dozen of different allergens.
The Phadiatop® test is a blood qualitative test for
the presence of sensitization: a positive result means that the patient
will most probably be allergic, while a negative test means the patient
will most probably not be allergic. This test is used as a screening
method for allergy.
It has been estimated that a person will come in
contact during lifetime with thousands of substances capable of inducing
Fortunately, only a few of them will cause problems.
Finding the cause of allergy is sometimes a very difficult task, and the
number of tests to be performed for a patient is limited, specially in
children. People usually become allergic to substances they have a close
and frequent contact with: the more frequent and more intense a contact
with a substance, the more probable that one becomes allergic to it.
Therefore, the tests to be performed must be based on a detailed medical
record, to select the allergens which more probably are involved. For
instance, a child with conjunctivitis when near a cat, will probably be
sensitized to cat dander. When symptoms appear in Spring, in the
countryside, pollen allergy is probable. The specialist must know what are
the most relevant plants, molds or mites in the area. Sensitization to
pollen of olive tree is very common in the Mediterranean area, while
allergy to birch pollen is exceptional. The opposite happens in North
Europe countries. House dust mites species may vary according to climate
On the other side, it is essential to make a correct interpretation of
results of tests. Not seldom, a patient may have positive results in tests
against some allergens that are not clinically relevant, that is,
allergens which are not responsible for triggering symptoms in that
It is important to realize that sometimes symptoms appear when there is a
time coincidence of several factors which would not be able to induce
those symptoms separately (an amount of allergens together with a viral
infection, or exercise, or cigarette smoke, cold air, pollution,…).
This means that the physician who performs, reads and interprets these
tests must be a skilled specialist, with the necessary experience and
training to reach a accurate diagnosis.
General recommendations for indoor allergen avoidance.
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Allergen avoidance mesaures
These measures are intended to avoid as much as posible tose
potentially harmful substances found indoors, which can cause asthma and
other respiratory and skin symptoms. GENERAL RECOMMENDATIONS FOR THE
These measures are meant to be the ideal condition. As long as
they are correctly accomplished, the chances of relapse will decrease.
Allergen avoidance is most important in the bedroom, where the child will
be at least eight hours a day.
Animal furs and feathers are most allergenic. We must avoid having furred
animals (specially cats, dogs and hamsters) and feathered birds at home.
If a patient is allergic to them, keeping them may cause symptoms, and if
a patient is not still allergic, there is a very high risk to develop
allergy to them.
There must be no carpets. There must be no inside flowerpots, as a lot of
molds grow on soil. You can keep them outside.
Use plastic washable paints for walls, which must be even and plain. Wall
papers must be avoided.
Carry out daily cleaning with a hoover, or washing with water. Use wet
cloth for furniture. Do not use a broom or shake dust. Avoid strong odor
SMOKING IS STRONGLY DISCOURAGED, even if the patient is not at home.
Air-conditioners are useful, if cleaning and maintenance of filters is
Every time a patient comes into a house which has long been closed
(holidays), thorough cleaning must be made according to these measures.
MITES AVOIDANCE MEASURES:
- For daily cleaning use hoover and wet cloth.
- Replace bed and furniture materials of wool, cotton, fur, feathers
by synthetic material.
- Avoid carpets, upholstering, heavy curtains.
- If you are planning to move, choose a dry, sunny place.
MOLDS AVOIDANCE MEASURES:
- Avoid and repair dampness at rooms, kitchen, bathroom.
- Avoid indoor plants, flowerpots, dry flowers.
- Open windows for ventilation of humid, dark romos. Use anti-mold
- Clean filters on air-conditioners and dehumidifiers with anti-mold
- Dry clothes and shoes before putting them away.
FEATURES OF ROOM
- When posible, the room must be dry and sunny.
- Use plain wood or tile floor. Avoid carpets.
- Walls must be plain and covered with plastic washable paint. Avoid
wall paper or cloth.
- There should be no curtains, or at least they must be made of light
- Avoid unnecessary furniture. If you have a wardrobe, use it only for
season clothes, but do not store toys or books.
- Put away clothes into plastic bags.
- Try the child not to use the bedroom as a playroom.
- Avoid upholstering, toys, bookshelves, pictures, posters, furred
FEATURES OF BED:
- The mattress and pillows should preferably be made of foam rubber.
Mattress and pillow covers which do not allow the passage of mites are
recommended. Alternatively, a plastic protecting sheet may be used. No
mattress or pillow with wool, kapok, or feathers should be in the same
- Use synthetic blankets. Replace fill-in of feathers by synthetic
- Clean the bedroom every day, with Hoover or water; do not use a
- Expose bed to sun and air, and hoover mattress and pillow daily.
- Clean furniture with a wet cloth. Clean the inside of the wardrobe
in the same way daily.
- Once a week, clean walls with a wet cloth, rubbing them downwards.
- Change sheets twice a week, and wash them in hot water. Wash
blankets and curtains twice a month.
- Any other bed in the same room must have the same condition. In bunk
beds, the allergic child should use the upper bed.
- The regular use of acaricide products is recommended.