Re: how common is lupus without positive ana
Auggie, hi. My big-city doctors explained ANA in a way that made such sense to me.
The explanation I was given is that first there's SLE = systemic lupus, which I think of as "classic lupus". The ACR criteria describe this kind. People with SLE have met 4 or more criteria in their lifetime, but not necessarily all at once. You see varying figures that in SLE, 95% to 98% have a positive ANA. Dr. Wallace, his excellent hardcover, writes that in some people, ANA can a very long time to turn positive, even though the patient already meets multiple criteria; also that long-term steroid use can cause it to go negative. Subtracting out those two groups, it appears that a very low % of those with SLE are ANA-negative "just because"...
Then there's an intermediate form called SCLE = subacute cutaneous LE, which my city doctors view as a "subset" of SLE. It was first described in the late 1970's. Its name is confusing, as SCLE is most often more than "skin-only". People with it may meet fewer than 4 criteria, or may meet *more* than 4 criteria. There are two unique SCLE rashes, both of which tend NOT to scar or depigment. One rash is called SCLE annular; in mature form, lesions are targetlike circles with clear centers. The other SCLE rash is psoriasiform or papulosquamous; this one looks somewhat like psoriasis, but isn't. Most people with only SCLE rashes test positive for anti-Ro & are extremely photosensitive. And now comes the tricky part... It's thought that ANA in people with anti-Ro remains negative as much as 30% of the time; in these people it's thought that the anti-Ro somehow "masks" the ANA results.
Last there's DLE = discoid lupus. Its hallmark is coin-shaped rashes that tend to scar &/or depigment. People in this subset meet fewer than 4 ACR criteria & most are ANA and antibody-negative. Cosmetic damage can be profound.
(FYI, there are other varieties, but I'll stop at these 3.)
But my drs. strssed that your rash (or rashes, plural) doesn't define your Dx. Instead, it's the totality of symptoms and test results, and how that totality lines up with the ACR criteria. Further, they told me that "rashes cross subsets", and I eventually illustrated this by getting one single scarring "discoid" lesion, after 8+ years of having only SCLE nonscarring lesions. Similarly, people with SLE are also "eligible" for discoid & SCLE rashes, though the malar butterfly is the most common.
So it's a mistake for doctors to use ONLY rashes to determine the extent of your lupus. Plus...some people with lupus NEVER get any rashes at all!
Why I (kinda, sorta) know this: I was Dx'ed with the SCLE variant after pretty much a lifetime of episodic problems & 8 years of nonscarring targetlike rashes on arms/torso. At time of Dx, my ANA was negative but anti-Ro was positive. One of my city doctors called me "a subset of a subset". He meant that within the SCLE variant, I fell within the *further* subgroup that's ANA-negative.
Plaquenil & sun avoidance have helped me tremendously.
Have you perused the ACR criteria? Borrowed any hardcovers from your local library? (Dr. Daniel Wallace &/or Dr. Robert Lahita would be my top reco's.) And does anything above ring any bells? I hope you post more when you can. Bye for now. Best wishes, Vee
Last edited by VeeJ; 06-11-2008 at 11:37 AM.
Reason: added formatting