Allergy and allergy-like symptoms in 1,050 medical students

During a 10-year period 1,050 medical students were questioned regarding allergy and allergy-like symptoms and 612 of them underwent skin prick tests with dog, cat, timothy and birch allergens. Symptoms of eczema, asthma or non-infectious rhinitis, past or current, or current reactions to pollen, furred animals, dust, mould or food were reported by 46% of the students. Three per cent reported present eczema of the flexure type and a further 8% reported past symptoms of the same kind. Current contact e zema was reported by 7% and past contact eczema by a further 3%. Daily treatment with ointments was reported by 52% of the students with current flexure eczema and by 17% with current contact eczema. Current asthma was reported by 5% and past asthma by a further 3%. Of those with current asthma, 88% were allergic to pollens and/or furred animals and 57% used anti-asthmatic drugs for at least 2 weeks/year. Current allergic symptoms in the nose and/or eyes were reported by 29% and a further 2% reported past symptoms. Of those with current symptoms 64% were allergic to pollens and/or furred animals, as judged by the history and skin tests. Almost 60% of the students with pollen allergy used anti-allergic drugs for at least 2 weeks/year. Allergy to pollens was reported by 17%, to animals by 12%, to house dust by 10%, to moulds by 2% and to foods by 15%. Allergy reported and confirmed by a prick test was found in 8% against birch, 6% against timothy, 10% against cat and 5% against dog.(ABSTRACT TRUNCATED AT 250 WORDS)     

Environmental and Social Influences on Skin Test Results in Children

Skin tests with 13 inhalant allergens were performed in 788 children with respiratory allergy. Positive reactions were common to animal danders (65%), to grass pollens (55%) and to tree pollens (44%) but rare to moulds (13%) and to house dust mite (12%). Children exposed to cows, dogs or horses at home more often had skin test reactions to these allergens than the children not exposed, but reactions to cat dander occurred as frequently in children exposed to cats at home as to those not exposed. Reactions to three pollens occurred most often in children from upper social classes and from urban areas and reactions to house dust mite occurred most often in children from lower social classes and from rural areas. Children with positive reactions to house dust mite came from larger families than children with negative test results.     

Inhibition Experiments with Solid Phase Mite or Epithelia in House Dust Hypersensitivity

The present study was undertaken to verify that mites are not the only allergens in house dust extracts and that other allergens such as cat epithelia can also be responsible for house dust hypersensitivities detected both by house dust skin tests and house dust RAST studies. In order to determine whether mite or epithelia fixed on a solid phase could remove not only the IgE antibodies reactive with the homologous allergens, but also the IgE antibodies reactive with house dust allergens, the authors have absorbed 10 sera of house dust allergic patients with solid phase mite or epithelia. The absorption procedure removed a large part of the IgE antibodies reactive with specific immunosorbent (Dermatophagoides pteronyssinus or cat epithelia) and in the same way the IgE antibodies reactive with house dust immunosorbent. The percentage of RAST inhibition varied from 65% to 92% for Dermatophagoides pteronyssinus and from 65% to 94% for house dust in patients allergic to house dust and mite; the percentage of RAST inhibition varied from 67% to 92% for cat epithelia and from 73% to 90% for house dust in patients allergic to house dust and cat epithelia. This is in accordance with the hypothesis that house dust is not an allergen per se, but rather a complex mosaic of several allergens including mite, animal epithelia, etc.     

Positive skin tests to aero-allergens and month of birth

The month of birth distribution for 1301 French patients born between 1953 and 1975 with at least one positive skin test was compared to that of the whole population. A chisquare test was performed, and the expected birth month distribution of the groups calculated from the INSEE * data for 1953-1975. All patients underwent skin testing with house dust, Dermatophagoides pternyssinus (Dpt), cat and dog allergens, grass, tree and weed pollens, and moulds. The only study criterion was a positive skin test unrelated to any specific disorder. A significant difference in month of birth distribution was observed 1) for patients with positive skin test to grass pollen, with a high rate of births from January to May, and 2) for patients with mould sensitization, with a low rate of births in April, May and December. Tree and weed pollens, house dust and Dpt showed no significant relation with month of birth. For cat and dog allergens, the observed and expected distributions of birth month were similar. For the whole sensitized population the birth rate tended to be low in December except for the cat and dog sensitized. Our study confirms the well-known seasonal peak of births in the first 5 months of the year for grass pollen sensitized patients. No consistent monthly or seasonal tendency could be statistically demonstrated for other allergens except moulds.     

The frequency and severity of cat allergy vs. dog allergy in atopic children

Questions were put to parents accompanying 1238 children, 1 to 17 yr old, who had symptoms of respiratory tract allergy. Skin prick tests were then performed. Symptoms after exposure to cats and positive skin test results from cat hair extract were significantly more frequent than symptoms after exposure to dogs or reactions to dog hair extract. The prevalence of symptoms and positive skin test reactions to cat allergens increased with age, significantly more so than the reaction or symptoms after exposure to dog allergens. The greater frequency of sensitivity to cats was not caused by exposure to cats in more homes, since dogs significantly outnumbered cats as the household pet in both atopic and nonatopic families. However, greater intimacy of exposure to cats when they were present may have been a factor because cats, significantly more often than dogs, were inside the house and in the child's bedroom. Two subgroups were examined to determine whether those with cat sensitivity who owned cats had more severe symptoms than those with dog sensitivity who owned dogs. Numbers were small and differences not statistically significant, but those in the cat subgroup more frequently had persistent allergic nasal symptoms and abnormally low spirometric measurements than did those in the dog subgroup. Our findings indicate that children are more often allergic to cats than to dogs and suggest that the greater frequency of sensitization to cats may be due to increased intimacy of exposure to cats.     

Allergen specific IgGd antibodies in dogs with atopic dermatitis as determined by the enzyme linked immunosorbent assay (ELISA).

Allergen specific IgGd antibodies were detected by the enzyme linked immunosorbent assay (ELISA) in 89% of the 62 atopic dogs studied. Antibodies were found most frequently against house dust (47%), human dander (50%), grass pollens (58%) and spring tree pollens (43%). These antibodies were also found in 11 of 20 dogs with atopic symptoms but without immediate skin test reactivity to inhalant allergens. Agreement between the presence of skin reactivity and allergen specific IgGd titres ranged from one of 14 for cat dander to 22 of 34 for house dust. Among dogs with atopic symptoms but without skin test reactivity and specific IgGd titres to the respective allergens, the agreement varied between 28 of 54 for human dander and 67 of 68 for cat dander. In view of the value of the dog as an experimental model of atopic disease in man, further studies of the pathophysiological significance of IgGd antibodies are warranted. In addition, reconsideration of the diagnostic criteria for canine atopic dermatitis, as done by Hanifin & Rajka (1980) in man, seems indicated.     

Animal danders

Animals release proteins into their surroundings through secretions, as excretions, or as dander. The quantity of dander that is dispersed by cats, dogs, or humans is sufficient to supply food for dust mites and to supply easily measurable quantities of proteins in dust. Fel d 1, Can f 1, and human IgA or IgG can be found in microgram quantities in dust samples. Allergens also can accumulate from the urine of wild or pet rodents. For cats and dogs, the accumulation of dander particles is not related to the cleanliness of the animals. All animals, including humans, provide a fully adequate supply of organic material for bacterial growth in a carpet, provided conditions are sufficiently humid. The authors' preliminary results in Virginia do not find a significant difference in endotoxin between homes with or without animals. The likely explanation for the nonallergic IgG and IgG4 response to cat, dog, or rat allergens is high exposure to proteins from these animals. If the highest levels of cat allergen in a home can result in immunologic tolerance, it is unlikely that primary avoidance would be successful at reducing exposure. The data showing that 80% of Swedish children with cat allergies never had lived with a cat imply that the concentrations of cat allergen in schools or in houses without a cat are sufficient to cause sensitization. Primary prevention would be possible only on a community basis, which is unlikely to occur. Sensitization to cat, rat, dog, or mouse allergens consistently is associated with asthma. In symptomatic children with positive skin test results, there is a strong case for allergen avoidance and a clear need for controlled trials. Controlled trials of avoidance should include houses without cats and schools. Controlling exposure to cat allergens with the cat in situ requires aggressive measures, such as removing reservoirs, washing the cat, and air cleaning. Many allergic or symptomatic children who live with a cat do not have positive skin test results or positive IgE antibodies to cats. Avoidance measures related to animals should be recommended only for individuals with positive skin test results. Increasing evidence shows that exposure to cats, dogs, rats, and other animals can induce a form of immunologic tolerance without causing allergic disease, and it is important to understand why this change occurs with dander allergens rather than with all allergens. The most probable explanations are related to the form and quantity of airborne allergens.     

House dust mite and cockroach exposure are strong risk factors for positive allergy skin test responses in the Childhood Asthma Management Program

BACKGROUND: Children with asthma have a high prevalence of environmental allergies, especially to indoor allergens. The relationships of exposure to indoor allergens (dust mites, cat, dog, cockroach, and molds) and other host factors to allergy sensitization have not been evaluated simultaneously in a large cohort. OBJECTIVES: We studied 1041 children aged 5 to 12 years with mild-to-moderate asthma to determine risk factors associated with having positive allergy skin test responses to indoor allergens. Also, we described, compared, and contrasted 6 allergens in the home environments of these children from 8 North American cities. METHODS: Data were used from baseline visits of the Childhood Asthma Management Program. Patients' sensitivities to house dust mites (Dermatophagoides farinae and Dermatophagoides pteronyssinus), cats, dogs, cockroaches, and molds were examined for relationships to demographic variables, home dust allergen exposures, number of other positive allergy skin test responses, total serum IgE levels, and smoking in the home. RESULTS: San Diego (78.5%) and Toronto (59.3%) had the topmost percentages of homes with moderate-to-high house dust mite levels. Boston (21.5%), St Louis (16.3%), and Baltimore (13.4%) had the highest percentages of homes with detectable levels of cockroach allergen. For house dust mites, the higher the level of allergen exposure, the more likely patients were to have positive allergy skin test responses, with relative odds of 9.0 (95% confidence interval, 5.4-15.1) for those exposed to high mite levels (>10.0 microg/g dust) relative to those unexposed. Even exposure to low levels of mite allergen (0.020-2.0 microg/g) was found to be a significant risk factor for sensitization. For cockroach allergen, those with detectable home exposure were more likely to have positive skin test responses (relative odds, 2.2; 95% confidence interval, 1.3-3.8) than those with undetectable exposure. In contrast, levels of exposure to cat, dog, and mold allergens were not related to sensitization rates. For cat allergen, this may reflect lower rates of cat ownership among highly sensitized subjects. Furthermore, the number of allergy skin test responses that were positive, excluding the test for the outcome of interest for each model, and total serum IgE levels were strong independent predictors of sensitization. CONCLUSIONS: Levels of exposure determined by house dust analysis are important determinants of sensitization for dust mite and cockroach allergen. This relationship was not demonstrable for cat, dog, or mold allergens, possibly because of confounding factors. For all allergens studied, the degree of atopy, determined by the total number of positive skin test responses or by total serum IgE levels, is an important contributing risk factor for sensitization.     

Study on the clinical significance of pharmacia rast RIA in animal allergy

To study the usefulness of Pharmacia animal allergen discs, the specific IgE antibodies in the sera of patients with allergy to pet or laboratory animals were measured with the use of those discs. The coincidental ratio between skin test to cat hair and RAST to cat epithelium was 73.3%, however between skin test to dog hair and RAST to dog epithelium or dog dander it was 66.7% or 60.0%, respectively. The rate of RAST positive do dog dander was higher than to dog epithelium, and so it seems to be the optimum allergen for screening. The correlation between RAST value to dog epithelium and dog dander was good, but there was no relationship between cat and dog epithelium, it seems that cross-antigenicity is low. In laboratory animals, the rate of RAST positive was in decreasing order: guinea pig, mouse, rabbit, rat, hamster. The rate of RAST positive to serum proteins of rat and mouse was lower than to epithelium and urine proteins. It seems not to be useful.     

Dissociation of house dust allergies. A comparison between skin tests, inhalation tests, specific IgE and basophil histamine release measurements.

The present study was undertaken to identify the most dominating allergens giving positive reactions both in vivo and in vitro, in patients with house dust (HD) hypersensitivity. Among 655 subjects with positive skin test reactions for HD, 469 (i.e., 71%) had positive reactions for Dermatophagoides pteronyssinus (D.pt.), and 186 (i.e., 28%) had negative reactions for D.pt.; among these 186 patients, 96% reacted to other different allergens, especially to animal epithelia. Challenge tests were performed in 52 patients. In 40 subjects with positive skin tests to HD and D.pt., all gave positive reactions to both tests. Among 12 patients, negative to D.pt. but positive to animal dander, provocation tests confirmed hypersensitivity to animal dander and absence of reaction after inhalation of D.pt. extract. Laboratory studies used specific IgE determinations (RAST Phadebas) and histamine release from human leukocytes. Of 240 HD-hypersensitive patients with serum IgE to HD, 204 also had positive RAST results for D.pt. and 36 for other allergens, there was a high incidence of cat dander (29/36). In a total of 13 dust-allergic people with positive skin tests for HD and D.pt., the relative cell sensitivity for these two extracts was determined from the allergen concentrations, which elicited 50% histamine release. The same biological parameters were determined in a group of 10 patients with positive skin tests to HD and cat dander, and negative skin tests to D.pt., for D.pt., HD, and cat dander extracts. Patients having positive skin tests to HD and D.pt. were also good histamine releasers for these two allergens. On the other hand, we could demonstrate that leukocytes from patients negative to D.pt. were really hypersensitive to cat dander. Our results demonstrate that neither HD skin tests nor HD RAST can characterize the effective allergens responsible for HD hypersensitivity. Identification of the major allergens present in HD, variable in each individual case, could aid toward more specific diagnosis.     

Classification of allergens by positive percentage agreement and cluster analysis based on specific IgE antibodies in asthmatic children]

Classification and characterization of allergens is important because allergic patients are sensitized by a variety of allergens. One hundred and sixty-one sera from asthmatic children were investigated for specific IgE antibodies against 35 allergens including 20 inhalants and 15 foods by means of the MAST method. We assessed the allergenic properties of the allergens based on positive percentage agreement and cluster analysis. There was a high positive percentage agreement of specific IgE antibodies between house dust and Dermatophagoides spp., a relatively high agreement between 5 molds, cat and dog epithelium, mugwort and wormwood and 5 grasses. Among the food allergens, the positive percentage agreements were relatively high, especially between cow's milk, casein, cheese, and between 3 cereal grains. In the cluster analysis, house dust and Dermatophagoides spp. made a big cluster; therefore 32 allergens except house dust and mites were analyzed. From the results of the cluster analysis, the major cluster consisted of (1) ragweed, (2) mugwort and wormwood, (3) timothy, sweet vernal, velvet and cultivated rye, (4) wheat, barley and rice, (5) molds, (6) cow's milk, casein, soybean and cheese, (7) shrimp and crab, (8) egg white, (9) Japanese cedar, (10) dog epithelium, (11) cat epithelium. The cluster of grass pollens and cereal grains made one cluster. These results tend to confirm the presence of species cross-reactivities within the major classes of allergens.     

Relationship of Allergen-Specific IgE Antibodies, Skin Prick Tests and Allergic Disorders in Unselected Adolescents

The relationship between serum levels of allergen-specific IgE (RAST) and skin prick test reactivity and allergic disorders was evaluated in 137 subjects randomly selected from an adolescent population. All subjects were prick tested with six common allergens, interviewed and physically examined. In addition, serum was collected for RAST analysis with three to six allergens. At least one positive RAST result (score 1-4) was observed in 40% and at least two positive RASTs in 22% of the subjects. Boys experienced more RAST reactions and generally with higher scores than girls. For instance, 26% of boys but only 11% of girls were RAST positive to timothy grass pollen. The correlation between prick test and RAST results was better with pollens than with house dust and animal epithelia. When the test results were discordant, the skin test was usually positive and RAST negative. Many of the small skin reaction (weal diameter 3-4 mm) were accompanied by a negative RAST. Respiratory allergy was closely connected with both positive skin test and RAST reactivity, while atopic dermatitis was less related. In 17% of the adolescents positive skin tests and in 14% positive RASTs occurred in the absence of any allergic symptoms. We conclude that a positive RAST score 3-4 to inhaled allergens is a strong indicator of clinical allergy but low scores 1-2 are frequently found in healthy young people.     

Influence of the Pollen Season on Immediate Skin Test Reactivity to Common Allergens

We studied the reproducibility of skin prick test reactions and tested 65 young men, picked from a population survey, in spring and fall. We used 16 extracts from two manufacturers with 12 common allergens. The extracts employed on both occasions were from the same allergen batches and the testing procedure was the same. Four subjects who reacted negatively in spring turned positive when retested in fall; the opposite happened to one subject. The result remained positive or negative on both occasions in 92%. The best reproducibility (96%) was obtained by pollens. The reactivity against tree and grass pollens was higher in fall than in spring; this is obviously a result of the immunologic stimuli induced by exposure to pollens during the season. The reactions caused by animal danders and house dust were, however, smaller in fall than in spring. This is believed to be due to young people being less exposed to indoor dusts in summer.
The immediate skin test reactivity is influenced by several factors; we would like to add one: the time of year when the test is applied. The reproducibility of skin prick test results is quite satisfactory when the problem is approached as presented here.     

Skin Prick Test Reactivity to Common Allergens in Finnish Adolescents

We studied 708 adolescents aged 15–17 years in the 9th grade of school in Imatra. Of the eligible population born in 1962 77% were included. All were skin prick tested with 16 extracts from two manufacturers with 12 common allergens, which included pollens, epithelia, mite, house dust and fish. At least one positive, immediate reaction (weal diameter 3 mm or larger) occurred in 49% and at least two positive reactions in 43% of those studied. The boys were observed to be significantly more reactive than the girls. The allergen preparations to which positive reactions were most prevalent were house dust, cat and horse epithelium, and mite extract. Large differences in the prevalence of positive reactions were observed with different preparations of the same allergen. Pollen allergens tended to cause the largest positive weal reactions, and the weal size distribution with some pollens was distinctly bimodal. A scheme for calculating allergen potency in histamine-equivalent-prick (HEP) units is presented. It is noted that the result is greatly dependent on the population group chosen for testing.     

A prospective study of allergy development in 158 children and 128 adults with new extensive exposure to furred animals

BACKGROUND: There is still controversy over whether exposure to furred animals increases or decreases the risk of developing sensitization and allergic symptoms to such animals, and there is a need for further knowledge on this subject. OBJECTIVE: The aim of this study was to follow allergy development in relation to new extensive exposure to furred animals in adults and children. METHODS: A total of 286 individuals, 128 parents and 158 children, were recruited from 68 families who intended to buy a dog or a cat, or where one child of the family intended to start riding a horse. Subjects were examined before the new allergen exposure and once a year thereafter for 5 years, in all at six occasions, and they also completed questionnaires covering allergy symptoms. Serum IgE antibodies to cat, dog and horse were determined each year, and fur allergens from beds and living rooms were analysed. RESULTS: Two-hundred and fifty-six study subjects remained for evaluation, 37 of whom showed signs of allergic sensitization at the start of the study. Four children (11%) in this pre-sensitized group developed IgE antibodies to their new animal and six (16%) to another animal. Among the 219 participants who were not sensitized when entering the study, one male adult (0.4%) developed a sensitization to his new animal, and nobody developed sensitization to other animals. Pre-sensitized individuals had significantly more allergic symptoms at the study start, but the symptom scores did not change over time. CONCLUSIONS: When the first year of a human's life has passed, we have no strong evidence to recommend avoidance of a domestic animal in order to prevent new allergy development, even if there are known allergies in the family or if the individual is sensitized and has allergic symptoms to another allergen. Five years exposure to new fur allergens does not seem to influence sensitization to these animals in either sensitized or non-sensitized children and adults.     

Allergenic materials in the house dust of allergy clinic patients.

INTRODUCTION: Environmental agents including animal, fungal, tree, and weed antigens are known to cause allergic rhinitis and asthma. The following study was performed to measure the antigen concentration of several of these in house dust of children seen in an allergy clinic. Comparisons are made between household allergen levels of children seen for asthma and children seen for other reasons. METHODS: Dust samples were solicited from patients in a pediatric allergy specialty clinic and other individuals associated with the clinic. Persons submitting dust were asked to complete a questionnaire describing their house. Samples were extracted, centrifuged, and filtered for sterility. Samples were stored in 50% glycerol at -20 degrees C. Specific antigens for Alternaria, Cladosporium, Aspergillus, Candida, Dermatophagoides farinae, cat, dog, oak, fescue, ragweed, plantain, and cockroach were measured using inhibition assays developed with whole antigen extract. Allergens Der p1, Der f 1, Alt a 1, and Alt a 70 kD were measured using double monoclonal antibody assays. RESULTS: Significant concentrations of whole antigen from cat, dog, oak, Alternaria, and Cladosporium were detected. Between 0.1 and 18 microg of Der f1 and Der p1 per gram of dust were also measured. Alt a 1 and Alt a 70 kD levels varied between 3.0 and 1000 U/g of dust. Significant positive correlations were observed in levels of dust mite and Alternaria allergen for patients with an evaluation of asthma. CONCLUSIONS: We found measurable levels of fungal antigens (Alternaria, Cladosporium), mite antigens, and animal antigens (dog and cat) in the majority of dust samples in this self-selected set of allergy clinic patients. Specific allergens Alt a 1, Alt a 70kD, and Der p 1 were significantly higher in the homes of asthmatic patients when compared with patients seen for reasons other than asthma. These studies support the hypothesis that fungal allergen exposure is an important component in the pathogenesis of the clinical condition known as asthma.     

Allergy to iguana

BACKGROUND: Furry animals produce allergens that can cause allergic rhinitis and asthma. In contrast, scaly animals, such as lizards, are assumed not to be allergenic. OBJECTIVE: We sought to evaluate a 32-year-old man who complained of allergic rhinitis and asthma symptoms that occurred exclusively in his own home. He had dogs and cats at home but denied any increase in symptoms specifically associated with these pets. Skin prick testing initially performed to 42 common aeroallergens, including cat, dog, and house dust mite, elicited negative results. He later reported that the symptoms were worse on exposure to his pet iguanas. METHODS: Skin prick tests were subsequently performed to an extract made from scales from his pet iguana. Extracts were also prepared from several zoo reptiles. Immunoassays for IgE antibody, as well as IgE immunoblots, were performed by using these extracts and the patient's serum. RESULTS: The skin prick test result with the pet iguana scale extract was positive. The patient's serum contained IgE antibody to his own pet iguana and to a zoo iguana. CONCLUSION: Our patient's history, skin test results, and in vitro studies clearly demonstrate that he is allergic to iguana. Physicians should be aware that such allergy to scaly pets may occur and should not restrict history taking to questions about furry pets.     

Histamine-Dependent Allergy Blood Test

Allergen-mediated histamine release from human leukocytes represents an important model for in vitro studies of allergic reactions. The purpose of this study was to determine whether the measurement of histamine released in allergic patients by radioenzymatic assay following mixing of their blood with common allergens represents a reliable index for diagnosis of atopic allergy. Three categories of allergens were used: 1) house dust and mite; 2) cat and dog dander; 3) trees, grasses and ragweed mixture. The presence of allergy was established by clinical history and intradermal skin testing in the study group of 150 patients. A significant allergen-mediated histamine release ranging from 4 to 65% of the total blood histamine content was observed in 96% of the patients with skin test sensitivity of greater than or equal to 3+. There was a significant correlation between skin testing and histamine release in terms of the allergens causing the response. Thus, the measurement of histamine by radioenzymatic technique following its release in blood in response to allergen challenge represents a clinically useful in vitro test for the diagnosis of atopic disease.     

Rhinitis in adults

Rhinitis is a very common disorder caused by inflammation or irritation of nasal mucosa. Dominant symptoms are nasal obstruction; however, in some patients, runny nose, excessive sneezing or nasal itch may be the most bothersome symptoms. The most common causes of nasal inflammation are viral infections and allergic response to airborne allergens. Response to irritants may cause similar symptoms, although signs of inflammation may not always be present. Viral rhinitis is lasting up to 10 days and it is part of the common cold syndrome. In short-lived rhinitis, lasting for 7 to 10 days, sometimes it is not easy to differentiate between the potential causes of the disorder, if general symptoms of infection like fever and malaise are not present. In long-living rhinitis, it is important to differentiate between infectious, allergic, non-allergic non-infectious rhinitis, and chronic rhinosinusitis. Itch and ocular symptoms are more common in allergic rhinitis, while other symptoms like nasal obstruction, rhinorrhea and sneezing may affect patients with allergic and non-allergic rhinitis. Patients with allergic rhinitis often have symptoms after exposure to irritants, temperature and humidity changes, like patients with non-allergic rhinitis, and such exposure may sometimes cause more severe symptoms than exposure to allergens. Sensitivity to a non-specific trigger is usually called non-specific nasal hyperreactivity. Allergic rhinitis occurs due to immunoglobulin E (IgE) interaction with allergen in contact with nasal mucosa in a sensitized patient. Sensitization to certain airborne allergen, like pollens, dust, molds, animal dander, etc. usually occurs in families with allergy background, which is helpful in making diagnosis in patients who have rhinitis in a certain period of the year, or aggravation of nasal symptoms occurs in the environment typical of certain allergen. The diagnosis is clinically confirmed by proving sensitivity to certain allergen on skin prick test, and by proving specific antibody IgE in patient serum. Allergic rhinitis is categorized according to sensitivity to allergens that occur seasonally, like pollens, or to allergens that are present all year round, like house dust mite, molds and animal dander, into seasonal and perennial allergic rhinitis. Allergy to pollens causes the same mechanism of inflammation in response to allergens, which is the result of allergen binding to specific IgE antibody; however, patients with pollen allergy usually complain more of sneezing and runny nose, whereas patients with allergy to perennial allergens more often complain of obstruction, with the episodes of sneezing and runny nose occurring only when exposed to higher concentrations of allergens (house cleaning, around pets). Treatment includes avoidance of allergens, medical treatment and immunotherapy (allergy vaccines, tablets with allergens). Avoidance of allergens means reduction of environmental allergen load to the respiratory system including workplace, which is not easy to accomplish. Medical treatment is usually necessary to control symptoms, and it includes antihistamines, nasal or in tablets, and nasal glucocorticoids (steroids). Antihistamines should be second generation, which do not cause sedation, and such treatment shows more efficacy on runny nose, sneezing and nasal itch than on nasal stuffiness. Nasal steroids are more potent in improving nasal patency than antihistamines, and are at least as potent in the control of all other nasal and ocular symptoms. Nasal patency may be improved by nasal or oral decongestants, but such treatment should be reduced to as short period as possible, since after several days of using nasal decongestants rebound congestion may occur and patients will need nasal decongestants to improve nasal airways even when allergens are not around anymore.     

Animal dander allergy

In a group of twenty-three atopic patients skin tests were performed with the dander allergens of horse, cat and guinea-pig, and with house dust and Timothy pollen allergens. A good agreement was observed between positive skin reactions and the results of RAST with these various allergens. In a number of cases, positive skin reactions were not related to the clinical histories. Likewise, positive RAST scores in several instances proved clinically meaningless. In patients with history-related skin reactions better correlation with RAST was observed. In such patients, skin reactions with photo-inactivated allergens remained strongly positive.