Are there any side effects to taking antihistamines for rashes over a long period of time?

I agree with the views expressed by the other doctors. Oral steroids have anti-inflammatory effects and can help your cystic acne and rash. However, long term use can cause a lot of other side effects and it is not recommended as the treatment for cystic acne. In fact, with continued use, you may notice even more acne lesions appearing as long term steroid use can aggravate acne. There are many other good treatments available for cystic acne. You should also get your other skin rash examined to determine the cause. While it responds to steroids, it again is not a recommended long term.

Thank you for posting a question. This is a complex question, which warrants proper questioning and examination by a qualified doctor. Any answer we give here will be difficult to answer your question with proper justice. Depending on your weight, 20mg of prednisolone is usually considered low dose and it is usually not expected to have these side effects especially when the course is so short as well. (perhaps you can consider to see a doctor to check if you have other medical problems) Most of your symptoms are non specific, and as such answers will probably be non specific as well.