Many physicians find it tricky to speak “dermatology” – to truly describe a rash and then provide a good differential diagnosis and consider further work-up. Dermatologist Dr. Bonnie T Mackrool reminded the audience that language does matter – “it’s all about the MORPHOLOGY” and then arriving at a good differential diagnosis.
When differentiating between acute and chronic lupus, important mimics of these types of skin lupus should be considered. Discoid lupus rarely transforms to SLE (~5% cases), but other forms of skin lupus including acute cutaneous (eg. Malar rash), subacute cutaneous lupus and bullous lupus, are seen more commonly with SLE. Psoriasis can mimic all subtypes of skin lupus including discoid. Asking about photosensitivity is also important.
Another good reminder is that more than one process going may be going on. Don’t forget to look for fungal skin infections (eg. Tinea) especially when the rash worsens instead of getting better. Important treatment modalities that can help skin lupus include sun protection, UVA shielding (houses, cars), topical steroids (but appropriate to location of body), antimalarials and systemic immunosuppressants (eg. Methotrexate, mycophenolate, azathioprine).
Patients with suspected cutaneous lupus need the expertise of a dermatologist - but it behooves the main caregivers of the lupus patient (often the rheumatologist) to have a reasonable skill set in identifying important skin disease to help with treatment.
Dr. Stephanie Keeling is an Associate Professor at the University of Alberta. Her research interests include lupus and connective tissue disorders.
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