A multivariate method for providing a clinical diagnostic support for allergic diseases, comprising the steps of a) acquiring data relating to: i. an allergy history of a patient by recording the seasonality of symptoms, ii. skin allergy test results, iii. laboratory test results of specific IgEs for allergen extracts and/or for allergenic molecules, iv. a local pollinic calendar, v. meteorological data, vi. environmental pollution data; b) assigning a Symptoms Medication Score derived from the data acquired in steps i., ii. and iii. in the form of a Rhinoconjunctivitis Total Symptom Score (RTSS), Average Combined Score, Averge Adjusted Symptom Score (AdSS), Rescue Medication Score or Daily Combined Symptoms Medication Score (dCSMS), c) detecting the most relevant allergen (s) for the patient by means of a computer based decisional procedure based on the assigned Symptoms Medication Score, correlated with the data acquired in steps iv., v. and vi., wherein the computer based decisional procedure includes Principal Component Analysis, Canonical Correspondence Analysis, Principal Coordinates Analysis (PCooA) and/or clustering and/or Linear Discriminant Analysis, Quadratic Discriminant Analysis, Partial Least Square Analysis and/or Artificial Neural Networks and/or Support Vector Machines, d) wherein detecting the most relevant allergen for the patient comprises correcting data for a pollen/inhalant allergen concentration by the Specific Activity of pollen/inhalant allergen for the patient, wherein said Specific Activity being the ratio of specific IgEs concentration detected in the patient with both allergenic extracts and allergenic molecules of selected pollen/inhalant allergens, to the total IgE concentration for that patient. a) acquiring data relating to: i. an allergy history of a patient by recording the seasonality of symptoms, ii. skin allergy test results, iii. laboratory test results of specific IgEs for allergen extracts and/or for allergenic molecules, iv. a local pollinic calendar, v. meteorological data, vi. environmental pollution data; i. an allergy history of a patient by recording the seasonality of symptoms, ii. skin allergy test results, iii. laboratory test results of specific IgEs for allergen extracts and/or for allergenic molecules, iv. a local pollinic calendar, v. meteorological data, vi. environmental pollution data; b) assigning a Symptoms Medication Score derived from the data acquired in steps i., ii. and iii. in the form of a Rhinoconjunctivitis Total Symptom Score (RTSS), Average Combined Score, Averge Adjusted Symptom Score (AdSS), Rescue Medication Score or Daily Combined Symptoms Medication Score (dCSMS), c) detecting the most relevant allergen (s) for the patient by means of a computer based decisional procedure based on the assigned Symptoms Medication Score, correlated with the data acquired in steps iv., v. and vi., wherein the computer based decisional procedure includes Principal Component Analysis, Canonical Correspondence Analysis, Principal Coordinates Analysis (PCooA) and/or clustering and/or Linear Discriminant Analysis, Quadratic Discriminant Analysis, Partial Least Square Analysis and/or Artificial Neural Networks and/or Support Vector Machines, d) wherein detecting the most relevant allergen for the patient comprises correcting data for a pollen/inhalant allergen concentration by the Specific Activity of pollen/inhalant allergen for the patient, wherein said Specific Activity being the ratio of specific IgEs concentration detected in the patient with both allergenic extracts and allergenic molecules of selected pollen/inhalant allergens, to the total IgE concentration for that patient.