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Vapour rub reduced nocturnal symptoms in children with upper respiratory tract infection
  1. Ian Wacogne
  1. Birmingham Children's Hospital, Birmingham, UK

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Study design

Design Randomised, placebo-controlled trial.

Allocation Age stratified randomisation.

Blinding Partially double-blinded (investigators were blinded; ‘no treatment’ group was not blinded; the attempt to blind both treatment groups was likely ineffective).

Study question

Setting A paediatric outpatient practice in the USA.

Patients 144 children aged 2–11 years presenting with moderately severe upper respiratory tract infection (URTI) symptoms (cough, congestion, rhinorrhoea) for ≥7 days. Children with asthma, pneumonia, laryngotracheobronchitis, sinusitis, chronic lung disease or seizure disorder were excluded.

Intervention Participants were allocated to one of the following: (1) vapour rub (petrolatum containing camphor, eucalyptus oil and menthol; n=44), (2) petrolatum ointment (used as a placebo; n=47); or (3) no treatment (n=47). Parents of children in the vapour rub and the petrolatum group were ‘blinded’ by applying vapour rub under their own noses before they opened their child's treatment. The treatment was applied to the child's chest by the parent 30 min before bedtime.

Outcomes Parental report of URTI symptoms during the night preceding recruitment and the morning after the intervention on 7-point Likert scales. Items included in the survey were cough frequency, cough severity, severity of congestion, severity of rhinorrhoea, child's ability to sleep and parent's ability to sleep. Adverse effects were also recorded.

Follow-up period A single night.

Patient follow-up 138 (95.8%) participants completed the study.

Main results

Cough frequency, cough severity and severity of nasal congestion were improved by vapour rub treatment compared to no treatment (p≤0.01 for each item); the differences between the vapour rub and petrolatum groups were not statistically significant. There was no difference between the three treatment groups regarding the severity of rhinorrhoea. The child's and the parent's ability to sleep was improved more with vapour rub than with either of the other two interventions (p<0.05 for all comparisons). Adverse effects in the vapour rub group (mainly a burning sensation of the skin, nose or eyes) were mild and transient.

Conclusion

Vapour rub provides some symptomatic relief from nocturnal URTI symptoms based on parental reporting. Vapour rub treatment was associated with better sleep for both children and their parents.

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Commentary

Most of us will have dismissed vapour rub as an old wives' treatment many years ago. This study, funded by a vapour rub manufacturer, seeks to challenge that rejection.

Many people reach for a remedy containing aromatic compounds such as camphor, menthol or eucalyptus oil when they have nasal congestion. Their minimal impact in reducing congestion is over-interpreted by the user due to the fact these compounds stimulate TRPM8 cation channels to signal ‘cold’. This leads to, as the adverts carefully understate it, “a feeling that you can breathe better”. A vapour rub would, in theory, work in a similar way.

How would you design a trial to test the beneficial effect of vapour rub in children with URTI? The trial would require a number of characteristics. First, it would need to be blinded. But how do you blind here? With difficulty, it seems. Blinding seeks to render the participants and/or assessors unaware of which treatment has been administered. The children were asked not to tell their parents if their treatment smelt. Reliability of secret keeping in children aside, if one of the treatments gets, literally, right up your nose, will you fail to notice this? Additionally, only those randomised to a petrolatum placebo – and not those randomised to ‘no treatment’ – were blinded. Importantly, the latter group used more remedies independently of the study.

Second, you need some sort of objective measurement of a good outcome, a measurement which will not necessarily be easy to influence if the participant has an idea of which study arm they were in. Here, the researchers used subjective parental assessment, on an Likert scale, of their child's symptoms the night before and the morning after the treatment.

When I’m reading studies about therapy, I’m also looking for the risk of harm. No serious side effects were reported in this study, but the authors do mention the risk of seizures in camphor poisoning. A PubMed search reveals that this has mostly been noted following camphor ingestion, although it has also been reported after repetitive skin application using an unregulated imported compound.1 Furthermore, data from animal models suggest that camphor-containing vapour rub increases respiratory tract secretions, which may result in mucus obstruction of small airways.2 Additionally, as with many topical treatments, it can be pretty unpleasant if it gets in the eyes or on mucous membranes.

Here's an ungenerous way of framing the results: in this manufacturer-funded study, in a group of children with respiratory symptoms given vapour rub, whose family could easily guess that they were getting treatment, parents were more likely to report improvement the morning after applying the treatment.

Here's a generous way of framing the results: in the group of children given the vapour rub, parents reported better sleep and fewer coughing symptoms the following morning.

The better sleep and less coughing might have been due to a number of effects. But as a parent, and even if you knew it was just you feeling a bit better about it all after reading this report, would you apply this treatment? Thinking about it, I’d be tempted, but I would know I was doing something not yet on a firm scientific footing. I would definitely find it hard to recommend this treatment to families, despite the apparent positive outcome apparent after a superficial read of this paper.

References

Footnotes

  • Sources of funding The study was supported by grants from Procter & Gamble (the manufacturer of the vapour rub) and the National Institutes of Health. The first author (IM Paul) has been a paid consultant for Proctor & Gamble.

Footnotes

  • Provenance and peer review Not commissioned; not externally peer reviewed.

  • Competing interests None.