Case Presentation
A 75-year-old woman with AQP4-IgG-positive NMO was started on weekly
intravenous eculizumab following suboptimal response to rituximab with
mycophenolate mofetil. Soon after the third infusion, she developed an
itchy skin rash involving all extremities that progressed over the
subsequent days despite diphenhydramine therapy. Due to progression of
the rash, the infusions were discontinued after the fourth one. Her
medical history included discoid lupus erythematosus (DLE) in remission
for 30 years and Sjogren’s syndrome.
Her physical exam was remarkable for NMO-related deficits (numbness and
weakness form the chest down, hyperreflexia and left eye blindness) and
the skin rash. All extremities were involved by well-defined,
coin-shaped, erythematous papules with varying size and scaling (Fig.
1). Her mucous membranes, nails, scalp, and hair were unaffected.
A dermatology evaluation
confirmed the clinical impression of this being a drug rash, as did
subsequent pathology. Skin biopsy of the left leg revealed a vacuolar
interface dermatitis (characterized by vacuolization at
the dermal-epidermal junction and lymphocytic inflammation of the
epidermis and dermis). Epidermal hyperplasia and dyskeratotic
keratinocytes were also present. The preponderance of inflammation over
epidermal necrosis favored a medication reaction over erythema
multiforme. Findings typical of drug-induced cutaneous lupus (basement
membrane thickening and mucin deposition) were absent.
Serological studies showed absence of antinuclear, anti-double-stranded
deoxyribonucleic acid, and anti-histone antibodies. Anti-Ro/Sjogren
syndrome A and anti-La/Sjogren syndrome B antibodies were positive.
(INSERT FIGURE)
She was placed on 50 milligrams oral prednisone four times a day for
four days with tapering. Prompt clinical improvement was noted with
complete resolution at 5 months.