Final answer:
Hydrocortisone cream treats the symptoms of the rash by reducing inflammation and relieving skin irritations, but it does not treat the underlying cause.
Step-by-step explanation:
The corticosteroid cream containing hydrocortisone treats the symptoms of Penny's rash by reducing inflammation and relieving minor skin irritations. It does not treat the underlying cause of the rash. Hydrocortisone works by reducing the secretion of histamine, which is a compound produced by the immune system in response to pathogens or foreign substances. By suppressing the immune system's inflammatory response, hydrocortisone helps limit inflammation, itching, and rashes.