Can systemetic lupus cause sudden severe hair fall?

Yes: Hair loss can occur with Lupus.

A Hairy Problem: Yes. A lupus diagnosis often involves many physical changes, including hair loss, which is a common side effect of lupus & the medications used to treat it. Recent severe illness, a thyroid problem,certain nutritional deficiencies, your genetic makeup & other specific skin diseases of the scalp can also cause hair loss. It's important to work with your doctor to figure out how to minimize it.