If you have bread but not breadcrumbs, I usually pop it in the oven on 250 for a while until it is dry. Then I run it in the Cuisinart or the blender to crush - you cold also hand crush it.
Substitutions
The oregano can be replaced with any other safe herb you can have.
Select breadcrumbs or cereal appropriate for your allergy set. Gluten-free crumbs or cereal will work fine.
Gluten: Gluten is a protein found in specific grains (wheat, spelt, kamut, barley, rye). Other grains are naturally gluten-free but may have cross-contact with gluten-containing grains. Look for certified gluten-free products if you need to avoid gluten. Find out more about wheat and gluten substitutions.