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: Angioedema , also known as angioneurotic edema or Quincke ' s disease , is a well - demarcated , localized edema involving the subcutaneous tissues that may cause upper - airway obstruction .
### Output Text:
Angioedema , also known as angioneurotic edema or Quincke ' s disease , is a well - demarcated , localized edema involving the subcutaneous tissues that may cause upper - airway obstruction . 