Diabetes weakens the immune system, leaving individuals more vulnerable to shingles and its complications, says an expert. Chickenpox may seem like a childhood illness of the past, but the varicella-zoster virus that causes it never fully disappears. Decades later, it can reactivate as shingles , causing an itchy, painful rash of blisters. The condition usually clears within weeks , but the burning or tingling pain can be intense.  Anyone who has had chickenpox is at risk of shingles and the