Q:

A patient of mine who has significant asthma with both and allergic and non allergic triggers is determined to use a humidifier in her bedroom this winter rather than just keep the heat down in the bedroom. She has hot water baseboard heat.

 

Is there a particular type of room humidifier that's better than any other? I have specified that she needs to monitor the relative humidity in the room also, to avoid over humidification.

 

Thanks as always for your help.

A:

Thank you for your recent inquiry.

I am not aware of any particular type of room humidifier being better for the asthmatic. There are a couple of nice websites that review the types of humidifiers available, and discuss humidifiers in general. You will find links to these sites copied below. However, neither suggests a particular brand or a particular type. In addition, a review of the medical literature failed to reveal any particular brand or type that might be best for the asthmatic.

As you well know, the most important aspect of using a home humidifier is keeping it clean. Pneumonia has been reported secondary to the use of home humidifiers (1). In addition, the use of a home humidifier has also been associated with worsening of asthma in children (see abstract copied below).

In summary, there is no particularly best type or brand of humidifier for use in the home of an asthmatic, at least to my knowledge. And there are some data which suggests that it is inadvisable to employ a home humidifier in the home of an asthmatic. Regardless of whether or not a humidifier is used, it is of course essential that it be kept clean to prevent the culture and spread of airborne microbes.

Thank you again for your inquiry and we hope this response is helpful to you.

Links:
http://www.mayoclinic.com/health/humidifiers/HQ00076/NSECTIONGROUP=2
http://www.asthma.ca/corp/services/pdf/asthma_humidifiers_vaporizers2_eng.pdf

Abstract:
Chest. 1991 Oct;100(4):922-6.
Childhood asthma and the indoor environment.
Dekker C, Dales R, Bartlett S, Brunekreef B, Zwanenburg H.
Source
Health Protection Branch, Health and Welfare Canada, Ottawa, Ontario.
Abstract
To investigate the influence of indoor air quality on respiratory health, a questionnaire-based study of 17,962 Canadian schoolchildren in kindergarten through grade 2 was carried out in 1988. The present report focuses on associations between several indoor environmental factors and childhood asthma. Increased reports of physician-diagnosed asthma were significantly associated (p less than 0.001) with exposure to environmental tobacco smoke (OR = 1.4), living in a damp home (OR = 1.5), the use of gas for cooking (OR = 2.0) and the use of a humidifier (OR = 1.7). Wheezing without a diagnosis of asthma also was associated (p less than 0.01) with environmental tobacco smoke (OR = 1.4, home dampness (OR = 1.6) and humidifier use (OR = 1.4), but not with gas cooking. Thus, several modifiable risk factors for respiratory illness may exist in Canadian homes. Further research is required to determine the nature of these cross-sectional observations.

Reference:
1. Harris AA. Community acquired pseudomonas aeruginosa pneumonia associated with the use of a home humidifier. Western Journal of Medicine 1984; 141(4):521-523.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology