I have a Lupus question?

Okay, a friend of mine has Lupus, and she gets sunburned very easily.... I know that someone who has lupus is very sensitive to sunlight, so that's not my question. But what I was thinking, was that when she get's sunburned, it takes about 4 months for the burn to heal. I was just wondering if lupus can cause this. It makes sense, because her ammune-system is weak(she gets infections very easily), but I want to know if that's what causes her to heal so slowly. Thanks!!! :)