Infantile asthma constitutes a particular entity. Its definition is not consensual and one of the principal issues is the prediction of the respiratory outcome in such infants. Many children identified before the age of five as having asthma had symptom remission, making it difficult to identify those whose symptoms will linger [1, 2, 5].

Few studies have been conducted on this topic in low and middle income countries. Our study identified factors associated with persistent asthma, then our findings were compared to those of previous studies conducted in developed countries. Among the 98 children enrolled in our study, two groups were individualized: transient wheezers (61.33%) and persistent wheezers beyond the age of 5 years old (38.77%). Their asthma was well controlled and partly controlled respectively in 72.44% and 27.56%.

Four predictive factors for persistent asthma were identified: familial atopy (adjusted odds ratio [OR] 4.76; 95% confidence interval [CI], 2.52–12.45; p < 0.001), passive smoking (adjusted OR 5.98; 95% CI 2.48–13.64; p < 0.001), poor control of asthma (adjusted OR 5.23; 95% CI 2.47–14.76; p 0.0013), and aerosensitization (adjusted OR 7.38; 95%CI 3.87–17.84; p < 0.001).

Exclusive breastfeeding until 6 months of age was noted in 19.38%. Neither the nonexclusive nature of breastfeeding nor the early introduction of cow’s milk protein was retained in the multivariate analysis as predictive factors for the persistence of infantile asthma.

The Tucson study individualized four groups of different outcomes (group of precocious and transient wheezers (19.9%), group of precocious and persistent wheezers (13.7%), group of late wheezers (15%), and group of non-wheezers (51.4%). Among infants who had at least an episode of wheezing before 3 years old; 40% remained symptomatic at the age of 6 years. The persistent wheezers belonged to the group of atopic with a positive PT [6, 10].

Other epidemiological studies brought comparable information: Maltret, Delacourt, and Boussetta found a rate of persistent wheezers respectively of 30%, 37%, and 42.8% [11,12,13]. We found a similar rate of 38.77%.

Through these studies different factors were analyzed to predict the respiratory outcome [14]. The consanguinity does not constitute itself a predictive factor of persistent wheezing apart from familial atopy [15, 16]. In our study, consanguinity was noted in 40.81% of cases. It was not associated with persistent wheezing (p = 0.82).

The male gender, admitted by several authors as predisposing to atopy and asthma, does not seem to influence the respiratory outcome of asthmatic infants [17,18,19]. We did not find a significant link between male gender and persistent wheezing in preschoolers (p = 0.98).

Familial atopy constitutes one of the main predictive factors for respiratory outcome. Maltret et al. found that 67.4% children with familial atopy continue to wheeze against only 17.1% of those who have no such family medical history [11]. Our results were similar; such infants belonged to the group of persistent wheezers in 58% of cases. Moreover, we found that familial atopy in relatives to the 1st degree was significantly and independently associated with persistence of respiratory symptoms in preschoolers (adjusted odds ratio [OR] 4.76; 95% confidence interval [CI] 2.52–12.45; p < 0.001).

Boussetta et al. find that infants with atopic mothers have 2.7 times more risk to keep wheezing at the preschool age. The paternal atopy does not influence, according to the same authors the respiratory outcome [13]. In our study, children had 3.6 times more risk to remain symptomatic in case of maternal atopy and no more risk in case of paternal atopy. However, this factor was not retained as an independent predictor of wheezing in preschoolers through multivariate analysis.

Maternal asthma constitutes, according to Boussetta and Martinez, a predictor of respiratory outcome [13, 20]. Concerning allergic rhinitis, the authors are not unanimous. Boussetta [13] and Martinez [20] do not keep it as a risk factor contrary to Maltret who establishes a significant relationship between maternal allergic rhinitis and persistent wheezing in preschoolers [11]. These differences can be explained by the heterogeneity of the population studies and by the heterogeneity of the diagnostic criteria of allergic rhinitis. In our study infants with familial allergic rhinitis belonged to the group persistent wheezers in 73.33% of cases but this factor was not kept as an independent predictor of wheezing in preschoolers.

Several studies conclude to the absence of preventive effect of the breast-feeding on allergy and even, for some, in its noxious effect. When a preventive effect is shown, it concerns only the non-allergic asthma [21, 22]. In our study, a non-exclusive breastfeeding during the first 6 months of life was not a risk factor for persistent wheezing (p = 0.82). The precocious introduction of CMP was neither kept as an independent predictor of bad respiratory outcome.

Progressive atopic dermatitis is commonly admitted as a factor of persistence of wheezing [18, 23]. We had not established such correlation because of the few numbers of infants with atopic dermatitis enrolled in the study.

An early age at the first episode of wheezing is significantly linked to the persistence of respiratory symptoms. The age threshold remains however variable. It is 6 months for Wennergren [24], 7 months for Bousseta [13], and 12 months for Korppi [19]. In our study, wheezing before the age of 6 months was significantly associated with persistence of symptoms in preschoolers.

The poor control of asthma constitutes according to most authors a predictor of bad respiratory outcome [1, 13, 24]. Our results were similar, poor control of asthma was related to persistent symptoms (adjusted OR 5.23; 95% CI 2.47–14.76; p 0.0013).

Several studies established a link between precocious allergic sensitization specially towards pneumallergens and persistence of wheezing [24,25,26] with 7 times more risk according to Boussetta et al. [13]. Our results were concordant with those of these authors.

The Saudi Initiative for Asthma panel recommends for early identification of the risk for persistent asthma among preschool children, to use the modified asthma predictive index (modified API). This tool when used for children with a history of ≥ 4 wheezing attacks (at least one is diagnosed by physician) and either one major (parental physician-diagnosed asthma, physician-diagnosed atopic dermatitis, allergic sensitization to at least one aeroallergen) or two minor criteria (wheezing unrelated to colds, eosinophils ≥ 4% in circulation, allergic sensitization to milk, egg, or peanuts) at 3 years of age, predicts a 4–tenfold increase in the risk of having asthma later in their childhood. On the other side, children with negative modified-API will have 95% chance of outgrowing their asthma later life [3].