Do you always get a rash with sciatica?

Sciatica or shingles: A rash is not one of the normal symptoms of sciatica. Something else to consider would be shingles, especially if the rash is in the same distribution as your pain. See your doc!

Sciatica: A rash is not associated with sciatica. Viral problems like herpes simplex and varicella can be latent in the nerve and cause irritation and rash during outbreak. Commonly caused shingles if recurrence of chicken pos virus (varicella).

No: Sounds like you may have shingles. I would see your doctor to confirm, but a rash is not a normal response to sciatica pain.