top layer of skin comes off when barely scratched

Hi.  I hope someone can help us.  

My daughter is nearly 17 years old.  Since she was 12, her body has been plagued by weird issues - sores that don't heal for months, pain and swelling in her tendons and ligaments in her hands, legs, and hips, scratches and mosquito bites that leave scars, migraines that last for days, a decreased cortisol level, various strange rashes, sparkling floaters in her eyes, continual protein and red blood cells in her urine, and many more things.  She has a positive ANA - speckled pattern, but no one has been able to officially diagnose her because her other blood tests are pretty normal- she has been told she has lupus that is not following the typical pattern, OR Sjogrens syndrome, OR psoriatic arthritis, OR mixed connective tissue disease, OR something else OR a combination of problems.

Recently when she was in the shower, she had an itchy area on her chest, so she scratched it.  On the place where where she scratched, the very top layer of skin came off, leaving her with very tiny pin ***** size drops of blood showing.  After her shower, she called me in to look at it.  This time, she took her thumb nail, scratched across the top of her skin, and again, the top layer of skin peeled off and she had the tiny drops of blood showing.  This has happened two more times, both while we were on vacation (she had been swimming).  

As the scratches have healed, they have turned a brownish tan color and are very visible on her skin.  

At this point she is scared to scratch anything - even when she is sweaty and itchy.  BTW, she is NOT DIGGING at her skin.  If she was to scratch a normal person in the same manner, there would be no marks at all!

Does anybody have any ideas?  I think that she has a collagen problem based on my reading, but I don't know who to take her to.  When I attempted to discuss this at her last dermatologist appt, her doctor was dismissive and said, "then don't scratch."  He didn't look at the marks, or listen to the problem.  I'm sorry, but I KNOW that is isn't normal to lightly scratch your skin when it is wet and then bleed afterward - unless a person is elderly - NOT 16 years old.  

Please let me know if anyone has any ideas that I could share with her rheumatologist.

Thanks