Mite counts and tests for mite antigen were performed on samples of dust taken from the bedding of 53 children with mite-sensitive asthma. The samples from damp houses and the beds of enuretic children had markedly more mites and mite-antigen than those from dry houses. Although the predominant species was usually Dermatophagoides pteronyssinus, some of the beds in the damp houses were heavily infested with another pyroglyphid mite Euroglyphus maynei, so that this was the species found in the greatest numbers. D pteronyssinus antigen was found to be correlated broadly with the total mite count, but more antigen was present for a given number of mites in the mattresses than in the blankets. The children were randomly allocated into two groups, one of which carried out rigorous anti-mite measures. The amounts of dust and mite antigen were reduced, though not the numbers of mites. Peak flow readings were monitored in the two groups for eight weeks and a final assessment made by a paediatrician who was unaware of the allocation of each patient in the trial. No significant differences emerged in the progress of the two groups, both tending to improve. Measures designed to remove mites from bedding do not greatly benefit the majority of children with mite-sensitive asthma.There is a considerable body of evidence which suggests that the house-dust mite Dermatophagoides pteronyssinus is a major allergen in the provocation of allergic asthma.'-3 These mites are especially prolific in blankets and feather pillows and on the surface of mattresses.4-6 Sarsfield et at7 reported that a group of children with mite-sensitive asthma improved considerably when measures were taken to remove mites from their bedding. Their study did not include a control group, however, so it cannot be known whether the improvement was spontaneous or psychosomatic rather than a response to the removal of provoking allergens. A randomised controlled trial was, therefore, undertaken to evaluate the effects of anti-mite procedures on children with mite-sensitive asthma. Subjects and methodsSubjects for the trial were selected from among the children attending a paediatric outpatient clinic. They were all aged 4 years or over, with positive skin tests to D pteronyssinus (weal size

AIBSTRACT Twenty-one children with mite-sensitive asthma took part in a crossover randomised controlled trial of mite-free bedding. Each child was issued with a new sleeping bag and pillow for a month, and twice-daily peak flow readings were compared with those obtained during a month in the child's ordinary bedding. Seventeen of the children had higher mean peak flow readings during the period in the mite-free bedding (p < 00 1). The overall improvement was only modest, however, and some mites had appeared in most of the bedding by the end of the trial. New bedding may be helpful to patients with mite-sensitive asthma, but methods are needed to prevent colonisation by mites.In a randomised controlled trial among children with mite-sensitive asthma rigorous anti-mite measures did not seem to confer any greater benefit than a placebo procedure.' This may have been the result, in part at least, of the failure of these measures to eradicate mites from the children's bedding. A further trial was, therefore, conducted to examine the effect of a change to mite-free bedding. Subjects and methodsThe subjects were all children with mite-sensitive asthma who had taken part in the previous trial. Those who still complained of frequent symptoms and who seemed to be suitable on other grounds were asked to participate in a further study. This trial involved a complete renewal of bedding, and a crossover design was used. Each child was randomly allocated to a treated or a control group for one month, and the two groups were then transposed for a further month.During the "treatment" period each child was provided with a newly purchased sleeping bag and a new pillow, new blankets also being supplied if required. The child's mattress was completely enclosed in an impervious plastic bag. All other bedding in the child's bedroom was either enclosed in impervious bags or removed and replaced (if in use) by new sleeping bags and pillows. The carpets in the bedrooms were Address for reprint requests: Dr ML Burr, MRC Epidemiology Unit, 4 Richmond Road, Cardiff CF2 3AS. vacuum cleaned several times every week. The children were issued with peak flow gauges and they recorded three readings each morning and evening, the highest reading on each occasion being used in subsequent calculations. During the control period no special placebo procedure was adopted except in so far as the measures advocated in the previous trial were still being practised. Some of the sleeping bags, pillows, and blankets were sampled for mite counting when they were first issued and again (after being laundered) before being issued to the second treated group. At the end of the trial each mother was asked whether the child had been better or worse during the period in the sleeping bag.

SUMMARY Six very preterm (<32 weeks' gestation) infants who developed late-onset respiratory distress were each matched for sex and gestation with 2 control preterm infants. Radiologically and biochemically the diagnosis of rickets and rachitic respiratory distress seemed clear and the pattern conformed with other reports of the syndrome. The control infants were of similar gestational ages but there was a significantly higher incidence of pre-eclampsia in the pregnancies of index cases. Also significant was a prolonged illness of several weeks' duration in the index cases; this illness was either heart failure due to patent ductus arteriosus or prolonged ventilation in the early weeks of life for apnoeic attacks. Awareness of these 2 aetiological factors shows the necessity of monitoring such infants for evidence of rickets. The use of water-soluble antirachitic prophylaxis such as 1 oc-hydroxyvitamin D or I,25-dihydroxy-vitamin D is sometimes indicated.

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SUMMARY Serial saliva cortisol measurements were used to assess pituitary-adrenal function in a group of asthmatic children treated with beclomethasone dipropionate (400 ,ug daily). Asthmatic children who were not being treated with steroids and normal children were also studied for comparison. A diurnal cortisol rhythm was observed in all three groups. Early morning cortisol concentrations were significantly higher in the group treated with beclomethasone dipropionate than in the normal children; this may indicate a stress induced response to decreased morning peak expiratory flow. In both groups, plasma and salivary cortisol responses after adrenocorticotrophic hormone stimulation test were normal but peak cortisol concentrations showed a 7 fold increase over basal values in saliva compared with a three fold increase in plasma. Beclomethasone dipropionate does not suppress pituitary-adrenal function in children when used in recommended doses. Serial measurement of the salivary cortisol concentration is a simple, safe, and sensitive method for the routine monitoring of adrenal function in children treated with this steroid. Monitoring may be supplemented with an assessment of the adrenal response to adrenocorticotrophic hormone stimulation, if necessary.