My voice is my livelihood and I suffer with allergies at various times during the year. Here are a few tools and tricks to get your voice back where you need it.
Many vocalists inhale steam and it helps to clear up my voice. A famous vocal coach told me many of the recording artists she works with steam constantly while recording albums. I’ve found this steamer to be the best: http://bit.ly/steamvoice
Then, if your voice is getting swollen and you are sounding hoarse, these exercises by Dr. Ingo Titze with a smaller diameter straw are really helpful to get the voice properly placed. https://www.youtube.com/watch?v=0xYDvwvmBIM
The straw diameter is pretty important. A regular drinking straw is too wide and won’t provide enough back pressure. A coffee stirrer is usually a bit too narrow, but closer to what you want. I have found some black wrapped straws at various McDonald’s work perfectly. You should feel some restriction when doing the exercises. Don’t push too much, it shouldn’t feel like you’re straining. Want to order a bunch and not raid your local MCD? These are the perfect size: http://bit.ly/StrawPhonationStraws
If you try either of the above, I’d enjoy some feedback to see if it helps you as much as it helps me and others that have tried it.