Performing only ELISA against specific IgE is to less. You need more allergy tests e.g. skin allergy test.

As far as I know basic level of specific IgE is accepted to be in a range 0-0.35 IU/ml.

Values above 0.35 IU/ml would indicate allergy but as I said you need to perform other allergy tests as well.

No. In my opinion and experience there are no relationship between a specific serum IgE and clinical allergy.

It depend on environmental and genetic factors. In developed countries allergen specif IgE is far more associated with allergic symptoms than in developing countries, possibilty because in deleloping countries, people are more exposed to factors that imunomodulate allergy such as helminths, ancient microbiota etc. However in both situation if a particular subject has more genetical susceptibility to develop effector IgE, it will require a minor cut-off of a specif IgE to start a allergic symptoms and this person may have be polysenstized.

Neuza; In developed countries people have much more allergies and the incidence are increasing because they don´t contact early with allergens. So they develop allergy. In undeveloped countries people contact early with allergens so they develop tolerance. Is this more or less ? in which concerns Dermatology the coumtries of the north of Europe have much more atopic dermatitis than the south countries.

Hi Américo,

Since childhood, people in Europe get contact with polens, which by far are the most important allegens in this Continent. Even though, they are sensitized in early ou late chilldhood and became allergic. So, there is no tolerence to polens in developd countries. It has been reported for allergy to dust mites, that one can develop tolerence when is exposed to acarid allergen since birth. But, in my opinion, this fact is not well studied. From our data, 46 % of children are sensitized for regional allergens. But, much less have clinical manifestation of allergy, so other immnunological phenomena might explain the absence of allergic manifestation in sesnsitized people than tolerance.

In patients with rhinitis due to house dust mite sensitivity - they can be skin test negative and have negative IgE serology for HDM but be nasal provocation positive and have specific HDM IgE antibodies in the nasal secretion. It is the target organ that is crucial mediator "read out" for diagnosis

Yes, there is a minimal number of IgE requested to induce an allergic reaction: of the total 500,000 to 1,000,000 IgE antibodies present on the mast cell surface, only a threshold number of about 2,000 bridged IgE antibodies are required for degranulation and mediator release. This number of bridges might be possible to accumulate by more than one non-cross-reactive antigen and its corresponding IgE antibody; therefore, patients simultaneously exposed to several antigens experience more symptoms than monosensitized patients as showed by studies of Johansson (Allergy. 2006 Nov;61(11):1366-8).