[Respiratory sensitization to molds in children: myth or reality?]. / La sensibilisation respiratoire aux moisissures chez l'enfant: mythe ou réalité?

The authors have made a systematic study by PRICK-test and RAST, sometimes followed by a rhino-manometric provocation, of the frequency of sensitization to the two moulds Alternaria and Cladosporium in 200 "all comers" children in a paediatric consultation. The frequency was low, only 10% for those consulting in the groups of asthma, rhinitis, pollinosis, repeated respiratory infections and syndromes of obstructed expiration taken together, and 13% for allergic asthma only. This sensitivity is rarely isolated, but is most often accompanied, or complicated by, other pneumoallergens, such as dust, mites, pollens and sometimes cockroaches. It imposes certain particular clinical traits on asthma (summer asthma or recurring asthma) and in others appears to be strongly influenced by the habitat. The skin tests seem to be very weak and RAST insufficient to be sure of real sensitization. Diagnosis, always difficult, is probably best done by a provocation test (preferably rhino-manometry) and this jumps over the bundle of clinical and biological arguments, as well as being, at least in our country, the most useful mimic of atmospheric moulds. The authors insist on the importance of the interrogation which should be concerned with the chronological and environmental circumstances and all respiratory infections that are suspected of having an allergic factor.

[Bronchial response to carbachol and isocapnic hyperventilation in asthma]. / Réponse bronchique au carbachol et a l'hyperventilation isocapnique dans l'asthme.

Bronchial challenge tests with carbachol and isocapnic voluntary hyperventilation (IVH) were performed in 15 asthmatics on two separate occasions. For the IVH test, the subject inhaled dry air at 20-21 degrees C; respiratory frequency and tidal volume were controlled in order to obtain various 3 min levels of ventilation; isocapnia was maintained by adding CO2 to the inspired air. Bronchial response was assessed by measuring airway conductance (Gaw) with a plethysmograph. Individual dose-response curves were constructed, allowing the calculation of two indices: the slope of the dose-response curve and the value of the minute-ventilation (V25, expressed as percent of predicted maximal minute-ventilation), or the dose of carbachol (D25) causing a 25% decrease in Gaw. There was no significant correlation between the slopes of carbachol and IVH dose-response curves and between the values of V25 and D25. These data demonstrate that the IVH and carbachol tests cannot be used indifferently to assess bronchial responsiveness.