Clinical Circadian Behaviour of Infantile Allergic Rhinitis

In a retrospective study, Palhares observed that infantile allergic rhinitis symptoms are stronger at evening and in early morning and are milder around midday and early afternoon [1]. Further, in patients with mild allergic rhinitis, symptoms present irregularly with periods of amelioration and worsening. Thus, in a week, not every day the patient will have symptoms; also, in a year, not every month the patient will have complaints. Hence, allergic rhinitis is considered to follow both circadian and circannual variation [2].


Introduction
In a retrospective study, Palhares observed that infantile allergic rhinitis symptoms are stronger at evening and in early morning and are milder around midday and early afternoon [1]. Further, in patients with mild allergic rhinitis, symptoms present irregularly with periods of amelioration and worsening. Thus, in a week, not every day the patient will have symptoms; also, in a year, not every month the patient will have complaints. Hence, allergic rhinitis is considered to follow both circadian and circannual variation [2]. Therefore, the clinical evaluation of allergic rhinitis in children should take in consideration the frequency of symptoms and the circadian cycle [3,4]. In the present paper, we have collated a questionnaire to evaluate the circadian behaviour of allergic rhinitis symptoms and to help in the clinical evaluation of the patients.

Methods
This research was approved by the Committee of Ethics on Research of the Faculty of Medicine of University of Brasilia. This is a prospective study carried out at the outpatient service of General Pediatrics of University Hospital of Brasília. The service is a center for secondary care that also attends to the demands of primary care. The patients reach the service either spontaneously or referred from the prompt-attendance service of the same hospital. We followed the guidelines given by ISAAC group (1992) to select the children presenting with symptoms of allergic rhinitis such as nasal obstruction and rhinorrhea [5][6][7]. Children with other diseases, under chronic medications or who had not returned with the filled questionnaire were excluded. Since the normal distribution is more evident with sample size of 30 or more, the study was carried out until this number was reached. At the end of the consultation, the parents who concurred in participating in the study were asked to complete a retrospective questionnaire about the time of worsening

University of Brasília, Brazil
and amelioration of the symptoms ( Table 1). The questionnaire was prepared based on ISAAC and on Palhares [1,5,6]. They were also asked to complete a questionnaire where the symptoms have to be registered at each period of the day, during the following 7 days ( Table 2). The descriptive retrospective data were expressed in simple proportion and the prospective data were compared by Student´s t-test.

Results
Forty children were considered for the study out of which 10 were excluded -6 because they did not return in the following week (withdrawal), 2 because of incomplete filling of the questionnaire, 1 because presented only nocturnal snoring and 1 because the symptoms were completely relieved with cephalexin due to acute sinusitis.   Out of 30 children included in the study, 20 were boys and 10 were girls. Table 2 shows the distribution of age. Age varied from 1 to 10 years, but the most frequent age was of between two and half years and five years.
Data from the retrospective evaluation are shown in Tables 1,3 . The majority of patients presented symptoms that lasted three weeks or more. Nasal obstruction, rhinorrhea and cough were the frequently cited symptoms, out of which nasal obstruction was more common. Among the physical markers of allergy, Dennie-Morgan´s eye crease and a pale or violet nasal mucosa were the most prevailing signs compared to ulnar deviation of medium finger (Najar´s signal) [8] and signs of atopic dermatitis.
The retrospective data showed a circadian behavior along the day, where the period between midday and 16:00 was referred as a period of amelioration of symptoms, as well as the morning period after wake-up. Table 2 shows the frequency of symptoms reported by each patient along one week. In each period of the day, each patient could have presented, then, 0 to 7 events. Each child presented a distinct pattern of weekly behavior, which can be seen at the high values of standard deviations. We observed that the frequency of the symptoms were significantly reduced between midday and 16:00 hour. Though not statistically significant the frequency of the symptoms were more between 18:00 hour and bedtime.

Discussion
Diagnosis of allergic rhinitis is primarily clinical, as there is no specific diagnostic test [5,6,8]. The allergic tests can only point out to an allergic condition. They cannot rule out a non-allergic rhinitis. In a clinical situation, a diagnosis of allergic rhinitis is usually made by ruling out infectious causes of rhinitis as non-allergic non-infectious rhinitis are considered rare in children [1,5].
In the present study, in addition to the clinical history the diagnosis of allergic rhinitis was corroborated by the presence of allergic markers such as sibilance and external signs of atopy -Dennie-Morgan´s eye crease, atopic dermatitis, pale or violet nasal mucosa and ulnar deviation of medium finger [8][9][10]. We have not considered allergic salute and allergic crease as they are inconsistent presentations. Even so, there was one case whose diagnosis was changed to acute sinusitis, as the use of cephalexin completely suppressed the symptoms and the patient had never complained about nasal obstruction or rhinorrhoea before.
Comparing to the results of Palhares, the patients at outpatient service presented a different profile of main complaint; at promptattendance services, cough is the most common symptom during consultation, while at outpatients, the most common symptom was nasal obstruction, although cough was also present [1].
Prospective studies are more accurate than retrospective ones. In the present study, the comparison of retrospective data with prospective observation revealed that they were in accordance. To guide the treatment of some chronic diseases with subjective symptoms -such as migraine and benign vertigo -it is common to request the patient to fill a prospective questionnaire of symptoms.
Similarly, the prospective questionnaire used in the present study could help in the clinical practice. To those children with less symptoms, the treatment can be relied upon intermittent use of low dose anti-histaminics, while those with more frequent symptoms would need continuous treatment with higher dose drugs [3,10]. One of the paradigms of paediatric treatment is to use the less medication as possible at the lowest dosage during the shortest period as possible. Using the prospective questionnaire from our study, a doctor can have a general overview about the behaviour of the rhinitis of the given child and the treatment can be designed accordingly.

Medications in use
Amoxicillin: 2 (6%) Nasal budesonide (intermittent): 2 (6%) Anti-histaminics: 4 (13%) Inhaled phenoterol: 1 (3%) As a conclusion, the infantile allergic rhinitis present a nitid circadian behaviour, being less active around midday. Also, the registration of symptoms during a week revealed that there are patients with almost daily symptoms, but the majority of them present symptoms intermittently.