A steam inhaler can be a valuable tool in your asthma management program. Why? Because it helps to loosen nasal and sinus mucus that can further impede your breathing. So, while a steam inhaler does not directly help your asthma, it can certainly help your breathing.
Steam inhalers can also go to work directly on the inflammation and irritation in your nasal and bronchial passages. When these tissues are irritated the steam can be soothing. The use of a steam inhaler also encourages a calm and even breathing pattern, which can also be very helpful for asthmatics.
There are many steam inhalers on the market. When choosing a steam inhaler, your first concern should be your comfort and ease of use. You might want to keep in mind whether you will be the only user of the steam inhaler or not. If you will be sharing this unit you'll want to consider whether the unit is easy to clean and sanitize.
Also, since a steam inhaler will provide a nice, warm, humid location for mold and mildew to start, your steam inhaler should ideally come completely apart for cleaning. Breathing mold spores in could further irritate the nasal and bronchial airways that you are trying to open. In general, the unit should allow you to clean it effectively and ensure that you are not introducing allergens into your body with the steam.
Try to find a steam inhaler that allows you to breathe in the soothing steam and protects you from being burned at the same time. Burns are probably the only potential drawback of a steam inhaler. This is likely the most critical point for you, as the consumer.