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: We report a patient in whom hypersensitivity to carbamazepine presented with generalized erythroderma , a severe leukemoid reaction , eosinophilia , hyponatremia , and renal failure .
### Output Text:
We report a patient in whom hypersensitivity to <span class="chemical">carbamazepine</span> presented with generalized erythroderma , a severe leukemoid reaction , eosinophilia , hyponatremia , and renal failure . 