In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: A rare cause , drug - induced vasculitis , may result from the production of antineutrophil cytoplasmic antibodies ( ANCAs ) in response to a medication .
### Output Text:
A rare cause , drug - induced vasculitis , may result from the production of antineutrophil cytoplasmic antibodies ( ANCAs ) in response to a medication . 