Recent advances in immunologic reactivity in otitis media with effusion

Clinical expressions of food allergy

BACKGROUND

The perception, by both the public and health professionals, of the clinical expressions of food allergy (FA) varies widely, from one extreme of nonexistence to another extreme of causing almost every ailment. Critical investigations in recent years led to a better clarification, as well as a reasonable classification, of FA manifestations.

OBJECTIVE

To provide a differential diagnosis of adverse reactions to foods and a classification of well proven FA manifestations.

DATA SOURCES

Reviews and original articles published in peer-reviewed journals, as well as classic textbooks on FA.

RESULTS

FA can affect several body systems. The gastro-intestinal tract is probably the most affected organ, but it does not always exhibit overt symptoms. Cutaneous manifestations are next in frequency, and in some studies are the most frequent perhaps because they are visible. Respiratory symptoms as sole manifestations of FA are less common, but have high frequency in children with atopic dermatitis. Systemic anaphylaxis has been responsible for sudden fatalities, although the exposure was often to minute quantities of the offending food. Other rare manifestations have been reported and are probably underdiagnosed.

CONCLUSIONS

FA is defined as the immunologically mediated adverse reactions to foods. It can be expressed in a wide array of clinical manifestations, ranging from simple gastro-intestinal, cutaneous, or respiratory symptoms to fatal anaphylaxis. Studies are needed to verify some rare or anecdotal manifestations that have been reported but are still considered controversial.

[Serous otitis media and allergy in our health district]

We studied the role of allergic diseases in patients with otitis media with effusion (OME).

MATERIAL AND METHODS

The 40 patients diagnosed with OME in the Otorhinolaryngology Service in 2001 were referred to the Allergy Unit for evaluation. The patients were assessed through anamnesis, prick test and specific IgE determination for the allergens in our area.

RESULTS

In 72 % of the patiens allergologic study was negative. One patient had perennial rhinitis with sensitization to house dust mites and another had seasonal rhinitis with sensitization to Gramineae pollen. Five patients showed high total IgE. Two patients had positive skin prick test and specific IgE to Gramineae pollen but were asymptomatic and a further two patients had negative anamnesis and specific IgE to Gramineae and olive pollen, respectively.

CONCLUSION

Allergic disease does not cause OME except in some patients with allergic rhinitis.

Health care costs of allergic rhinitis-associated conditions vary with allergy season

BACKGROUND

Studies have documented how allergic respiratory symptoms vary with allergen levels, but the impact of allergen levels on health care expenditures for allergy-related conditions has never been shown using actual data on outdoor allergen levels. Evidence linking respiratory allergy to comorbid conditions has also been scanty.

OBJECTIVE

To investigate the link between respiratory allergy and presumably associated conditions by documenting seasonal patterns in their severity and co-occurrence, and to suggest a plan for future research.

METHODS

A retrospective, cross-sectional analysis of medical claims data from 1995 to 1996 were linked to monthly data from federal counting stations on outdoor allergen levels. Participants were employed persons and their dependents, living within 15 miles of an allergen-counting station, continuously enrolled in a health plan for 1995 and 1996, and identified through medical claims data as having asthma, allergic rhinitis (AR), migraines, sinusitis, tonsillitis, otitis media, depression, or anxiety disorder.

RESULTS

All conditions studied were more likely to occur during allergy season than during nonallergy season. For persons with health care claims for a condition of interest in both seasons, total health care costs during allergy season were significantly higher than during nonallergy season. Predicted condition-related expenditures were higher in allergy season for every condition even after controlling for the effect of AR.

CONCLUSION

Allergy effects appear to extend beyond AR symptoms. Other conditions may be affected by outdoor allergen levels even in the absence of AR symptoms, implying that these conditions may be etiologically related to allergy, irrespective of their co-existence with allergic rhinitis, further implying that allergic sensitization can independently affect different parts of the respiratory tract as well as the brain.

Unusual presentations of food allergy

OBJECTIVE

This presentation is designed to critically review information on presentations of food hypersensitivity reactions that may be considered unusual regarding the source or nature of allergen, route of exposure, or clinical manifestation.

DATA SOURCES

Information has been gathered primarily through a thorough search of the English literature relevant to human subjects. Some clinical cases were also included from the author's own clinical experience.

STUDY SELECTION

Information summarized here was critically selected on the basis of proven or acceptable scientific validity.

RESULTS

The findings indicate that food allergy presentation can be unusual in three main aspects. First, the offending allergen may not be the obvious food that was ingested or be a food protein incorporated in a nonfood product. Second, systemic reactions can be provoked by very minute quantities of food allergens that may even get access through noningestant routes, eg, inhalation, odor, skin contact, or mucous membrane contact. Third, the clinical manifestations are not limited to the few gastrointestinal, cutaneous, and respiratory symptoms with which we are generally familiar.

CONCLUSIONS

The extent of food allergy presentation is more than has been generally realized. Our awareness of such unusual presentations adds new knowledge and should prompt our interest in carefully evaluating patients with obscure allergic reactions for possible food allergy.

Allergy increases susceptibility to otitis media with effusion in a rat model. Second place--Resident Clinical Science Award 1998

To investigate the possible relationship between allergy and otitis media with effusion (OME), we investigated the hypothesis that allergen presentation to the middle ear causes functional disruption of the eustachian tube predisposing to the development of OME. Thirteen of 19 Brown-Norway rats were sensitized to ovalbumin, and the remaining 6 served as nonallergic controls. To mimic subclinical exposure to allergen, we transtympanically injected ovalbumin at a dose (0.01 mg) that produced no changes detectable by otologic examination. Next, both allergic and nonallergic rats were exposed to transtympanic injection of either low-dose (10 microg/mL) or high-dose (100 microg/mL) lipopolysaccharide to simulate bacterial exposure. The allergic rats were found to have larger middle ear effusions when exposed to high-dose lipopolysaccharide as compared with the nonallergic controls. This response could be inhibited by diphenhydramine. We conclude that allergen presentation to the middle ear of allergic rats causes eustachian tube dysfunction predisposing to OME.

Acute otitis media in children

Acute otitis media (AOM) is the most common reason parents bring children into the primary care physician's office. It is diagnosed by clinical symptoms of otalgia and often fever and irritability and by clinical otoscopy. Organisms common to the nasopharynx usually cause AOM. Many episodes of AOM resolve spontaneously. Because it is uncertain how many and which children will resolve without therapy, it is reasonable to treat all children with AOM with antibiotics. The first choice of antibiotics is amoxicillin. Other choices rest on a variety of factors.

Association of otitis media with effusion and allergy as demonstrated by intradermal skin testing and eosinophil cationic protein levels in both middle ear effusions and mucosal biopsies

This study was performed to ascertain the role of allergy, as defined by skin testing and histochemical markers, in the pathogenesis of otitis media with effusion (OME). A historical perspective of allergy as it relates to OME is presented. The study included 89 patients: 48 with persistent effusion but no recent acute infection, 25 with purulent OME complicated by a superimposed infection, and 16 control subjects. All 89 patients had persistent effusion for more than 2 months and subsequently required the placement of tympanostomy tubes. Allergy was defined using the radioallergosorbent test (RAST), serum immunoglobulin E (IgE) levels, and skin tests. Allergies were present in 97% of the patients with nonacute OME. The relationship between allergy and OME was corroborated clinically in 89% of patients and was also substantiated by elevated levels of effusion eosinophil cationic protein (ECP) in 87.5% of OME patients. Histologically, polyclonal antibody staining for ECP demonstrated the presence of eosinophils in middle ear mucosal biopsy specimens. This study confirms that OME is a sign of allergic inflammation in the middle ear that is associated with an increase in eosinophils and a concomitant release of ECP into the effusion in individuals with allergy demonstrated by skin testing.

Levels of Eosinophil Cationic Protein and Myeloperoxidase from Chronic Middle Ear Effusion in Patients with Allergy and/or Acute Infection

BACKGROUND AND OBJECTIVE: Allergy may play a role in the middle ear inflammation that leads to otitis media with effusion. The purpose of this study was to determine whether an elevated mediator correlated with the patient's disease and thus could be used to differentiate allergy vs. infection as the cause of the middle ear inflammation.

METHODS: We evaluated 57 individuals with otitis media with effusion, 32 with persistent effusion but no recent acute infection, 14 with recent infection and purulent otitis media with effusion, and 11 healthy subjects. The mediator activity of eosinophils and neutrophils in effusion was studied in patients characterized as having allergy by positive intradermal skin test results and positive radioallergosorbent test results. Eosinophils were characterized by measurement of eosinophil cationic protein in the effusion. Neutrophils were characterized by measurement of myeloperoxidase in the effusion. The levels of eosinophil cationic protein and myeloperoxidase in patients with and without allergy were correlated to patient history.

RESULTS: Significantly elevated levels of both eosinophil cationic protein and myeloperoxidase indicated that inflammation in the ear of patients with otitis media with effusion was characterized by a pronounced involvement of both eosinophils and neutrophils. Eighty-nine percent of all patients with disease had allergy. A higher ratio of myeloperoxidase to eosinophil cationic protein in patients with purulent otitis media with effusion indicated that in patients with a superimposed acute infection, neutrophil activity was increased even further. The level of eosinophil cationic protein was elevated only during the effusion of patients with allergies as compared with controls ( p < 0.01). Among 29 cases of nonpurulent otitis media with effusion, 96.5% had allergic immune-mediated disease proved by skin testing, which was related clinically to their ear disease. Eighty-nine percent (89.6%) of these patients had eosinophil cationic protein levels greater than 10 μg/L.

CONCLUSION: Middle ear eosinophil cationic protein may be used as a marker of related allergy.

Biochemical evidence of platelet-activating factor (PAF) in human middle ear effusions

Platelet-activating factor (PAF) is one of the most potent biological lipid mediators. This is especially true in relation to inflammation. In order to characterize the biochemical features of otitis media with effusion, the authors characterized and determined the concentration of the PAF present in human middle ear effusions obtained from 23 patients with otitis media with effusion. Each sample of middle ear effusion was divided into two groups: serous (n = 12) and mucoid effusions (n = 11). The platelet-activating factor activity was found mainly in mucoid middle ear effusions, and the amounts of PAF were higher in mucoid type (3.55 +/- 1.19 ng/g, mean +/- standard deviation [SD]) than in the serous type (0.44 +/- 0.19 ng/g). Phospholipids obtained from the middle ear effusions contained a large amount of lyso-platelet-activating factor, the biologically inactive precursor or breakdown product of platelet-activating factor. Based on these findings, it is suggested that platelet-activating factor may play an important role as a mediator of the inflammatory responses in the pathogenesis of otitis media with effusion.

The presence of eosinophil cationic protein in middle ear effusion

Eosinophil cationic protein (ECP) is probably responsible for the underlying inflammatory mechanisms seen in asthma. It can be modulated in vivo by immunotherapy or steroids, with an appropriate reduction in symptoms of respiratory tract diseases. ECP is an identifiable mediator in additional target organs involved in allergic reactions, making it of potential interest in the study of otitis media with effusion. A qualitative prospective study was designed to discover the relationship of ECP and serum IgE in patients with middle ear effusion and allergy, as demonstrated by RAST and skin testing. The concentrations of ECP in the middle ear fluid from 23 consecutive patients with otitis media with effusion undergoing the placement of tympanostomy tubes ranged from 2 to 1248 micrograms (normal serum ECP, 5 to 15 micrograms), with 87% being abnormally elevated. There was no correlation between an individual's ear and serum levels of ECP (r = 0.1672; p = 0.6232), suggesting a more localized process. There was no relation between effusion ECP and serum IgE (p = 0.0040). ECP from middle ear effusion did correlate with a patient's having allergy, as confirmed by RAST and skin testing (p = 0.0095). Mechanisms involving immune mediated disease in the middle ear, of which the eosinophil may be one participant, are presented.

Regional blood flow volume in the eustachian tube

Measurements of regional blood flow around the pharyngeal orifice of the Eustachian tube were carried out after topical administration of various inflammatory mediators in 14 mongrel dogs by the hydrogen clearance method. Histamine and platelet-activating factor (PAF) resulted in a significant alteration of blood flow volume. Histamine was found to induce a dose-response related increase, whereas blood flow volume tended to decrease in each concentration range in the series of PAF administration. There was no significant difference in blood flow between topical application of leukotriene C4 and leukotriene D4. It is likely that in upper respiratory tract inflammation, such as in otitis media and in nasal allergy, activated histamine and PAF affect the microcirculation of the tubal orifice. These results suggest that disturbance of the microcirculatory system in the Eustachian tube mucosa could be involved in the pathogenesis of chronic otitis media with effusion.

Effects of various inflammatory mediators on eustachian tube patency

The effects of several inflammatory mediators on the patency of the Eustachian tube were evaluated in 15 mongrel dogs. Histamine, leukotriene C4(LTC4) and D4(LTD4), and platelet activating factor (PAF) were perfused through the Eustachian tube of anesthetized dogs at concentrations detected in human middle ear effusion of patients with otitis media. The patency of the Eustachian tube was then evaluated by perfusion pressure and opening pressure. Histamine at concentrations of more than 10(-5) M caused increased tubal resistance and opening pressure rapidly. LTC4 and LTD4 caused a rapid increase of tubal resistance and opening pressure at far lower concentrations, i.e. 10(-12) M. Doses of PAF over 10(-9) M may cause an increase in the opening pressure. These results indicate that various inflammatory mediators are capable of affecting the Eustachian tube function.