Does steroid injections for Alopecia Areata cause bumps and infections? Especially on the beard?

This requires an in-person evaluation to determine if you have an infection. Steroids shouldn't cause infections in the beard. If you have progressive disease, I suggest oral steroids, or considering DPCP. Please see an expert for an evaluation.  Best, Dr. Emer.

If
you are having bumps or feel you have an infection in your beard / scalp you
should see a hair transplant physician or dermatologist.  Patients typically benefit from steroid injections
for alopecia areata if the injections are done properly.  At times when the steroid injections are too
deep, it may cause lipodystrophy, which the skin may appear depressed on the
surface.

There are "potential" side effects to many treatments. By potential, we nean there is a defined chance a person will experience this side effect and a chance they will not. Certainly, topical and injection forms of steroids can lead to folliculitis- but it's not all that common. They can be treated with topical acne medications or left alone to resolve with time. Steroid injections can be very effective in beard alopecia areata.

There are a few potential medical treatments for alopecia areata, including steroid injections. In order to fully evaluate you and discuss the potential treatment options, an in-person evaluation is necessary. 

My advise is to seek the opinion of a specialist in your area so that a full and proper in person assessment can be made. If you think that you may have folliculitus, it can easily be treated but you must first speak to a doctor to be sure. 

From what you describe, you are not the patient who can be treated or diagnosed over the internet. You need to see a doctor one on one.