As regards your most recent question about whether molds and fungi can live and grow in regulator hoses, the answer is yes, they can, but this occurs only in hoses that have somehow gotten damp inside. A properly treated & cared for reg system (e.g., tank not breathed dry, reg rinsed only while under pressure) will not get water inside. If you think that your hoses may be contaminated, replace them. Also, second stages should be periodically disinfected by soaking in a dilute bleach mixture or one of the many good commercial products designed for such sanitization (e.g., SaniZide Plus, Advance TBE, Bi-Arrest 2 & Confidence Plus).
As regards your original question about return to scuba following oral steroid treatment for lung inflammation, one would want current chest x-rays to be unremarkable and be confident that the inflammation had fully resolved and lung function returned to normal limits. Of course, the individual should also feel fit & ready to dive.
It is not clear from your description to date exactly what procedures your physician has applied in granting you clearance to dive, but some diving medicine experts feel that standard static spirometry is not adequate for this purpose and recommend an exercise provocation test. This is a procedure where you'll be allowed to administer your Advair and albuterol, and then be subjected to strenuous exercise during which periodic assessments of lung function are made. Your pulmonologist should be familiar with the technique.
This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.
Best of luck.
DocVikingo
