AANEM Connect

Thanks in advance: Has anyone treated patients with chilblain lupus who have severe symptoms of small fiber neuropathy? See questions at end of post. Appreciate your help.

The patient is a 45-year-old woman with 5 years of symptoms in the hands and 3 years of symptoms in the feet. Symptoms are sensitivity, swelling, pain with activity, redness with activity, and neuropathic pain. On exam she has visible edema and rubor in the extremities. No neuro deficits apart from altered temperature sense in feet. 

1) Derm workup: Skin biopsy with dermatology revealed chronic cutaneous lupus erythematosus, compatible with chilblains lupus. 
2) Neuro workup: Abnormal QSWEAT. Normal Therapath skin biopsy. Normal NCS (sural 15-20 uV). 
3) Rheum workup: CRP 0.6 (ULN 0.5), ESR 36 (ULN 20). Otherwise, extensive labs are normal including WashU sensory neuropathy Ab, paraneoplastic panel, CBC, CMP, cryoprotein, B12 681, CK 76, ferritin, C3, C4, proteinase 3, myeloperoxidase Ab, ANA, SSA, SSB, Sm, RNP, Scl70, Jo1, cANCA, pANCA, SPIE, FLC, HIV, Hep C Ab. A1c 5.5.  

Treatment trials:
1) For vascular component: Nifedipine caused swelling. Pentoxyfylline (Trental) 400 TID is helping with toe swelling. 
2) For neuropathic pain component: Duloxetine and pregabalin are helping a little. Side effects from low dose venlafaxine, gabapentin. Compound cream (ketamine and amitryptyline) didn't help. 
3) For immune process: On plaquenil 300 mg daily - unclear if helping. Prednisone 40 mg daily caused severe foot pain.

Questions:
- Have you treated patients like this?
- Any other ideas for workup? Genetic testing for small fiber neuropathy is pending. Genetic testing for genetic causes of chilblain is also pending (maybe her case isn't immune)
- Do you know how to order plexin antibody testing? 
- Any other ideas for treatment? We are going to try prednisone again at a lower dose of 10 mg daily.  

Thanks again. She is grateful for your input. 
 

Sarada