I am undergiong treatment for a non invasive bladder tumor
You can use topical steroid cream
Thanks for query ..
The rash on legs following BCG treatment for bladder cancer though rare but is known.
You can take Steroids orally for short term along with topical steroid cream to be applied over affected part of legs.
Continue taking anti histamine drugs .
Hope I have answered your query ,please feel free to ask if you have more questions,I shall be happy to help you
Thanks and Regards.