My sister has a rash on her arm…?
Okay, we went to the pool Tuesday. We used hypoallergenic sunblock because she's allergic, we figured that out when she was 6-7. The rash went away within a day or two. But this time, it's been here longer, and it itches like crazy. What's wrong?
Just because something is listed as hypoallergenic doesn't mean it's not possible to react to it. It just means that what triggers allergies in most people is reduced or removed.
It sounds like she's still allergic to something in the sunblock, and it has either worsened with age or changed somehow. To help it you might want to try putting hydrocortizone lotion on it to help with the itching, and washing or using cool compresses on the effected areas.