Linear IgA bullous dermatosis (LABD) is a rare mucocutaneus blistering autoimmune disease caused by IgA autoantibodies. Its clinical manifestation can be indistinguishable from bullous pemphigoid (BP), a similar autoimmune bullous disease caused by IgG and IgE autoantibodies. Although BP has been reported as an adverse cutaneous effect of immunotherapy, LABD has rarely been associated with immunotherapy in the literature. We present the case of a 67-year-old woman with metastatic ovarian cancer receiving anti-PD1 and anti-CTLA4 with new onset pruritic tense bullae to the trunk, hands, elbows (in annular distribution) that occurred after immunotherapy. Skin biopsy showed subepidermal blister with abundant neutrophils on H&E histology, and linear IgA staining at the basement membrane on direct immunofluorescence consistent with the diagnosis of LABD. The condition did not improve on initial prednisone taper, but blisters rapidly resolved a few days after initiation of dapsone therapy. We favor that our patient's LABD is secondary to her immunotherapy. Our case highlights the importance of both H&E histology and direct immunofluorescence in diagnosis of blistering disorders in patients on immunotherapy to help in choosing the most effective treatment option in an attempt to avoid discontinuation of immunotherapy.

Cutaneous leukocytoclastic vasculitis (LCV) is type of small vessel vasculitis that commonly presents as palpable purpura involving the lower extremities and buttocks. Approximately half of cases are idiopathic, but the disease may be triggered by infection, drug reaction, inflammatory disease, or other causes. We report a case of leukocytoclastic vasculitis secondary to the novel anticoagulant rivaroxaban (Xarelto®).

We present a rare case of dermatomyositis associated with nivolumab therapy for melanoma. Nivolumab is an immune checkpoint inhibitor that blocks the programmed death-1 (PD1) receptor and has a number of associated immunotherapy related adverse events. Although most are T-cell mediated, some are antibody mediated mimics of classical autoimmune diseases. We review the characteristics of other cases of anti-PD1 associated dermatomyositis and the recent literature to better understand how to classify and treat this challenging immunotherapy related adverse event.

Immune-related adverse events (irAEs) are common in patients receiving immune checkpoint inhibitors for metastatic melanoma and other advanced malignancies. Cutaneous, gastrointestinal, and endocrine (thyroid) irAEs are most prevalent, whereas neurologic irAEs are rare. We present a 73-year-old man with dementia and metastatic melanoma who developed immunotherapy-associated encephalitis and subsequently, interstitial granulomatous dermatitis with nivolumab/ipilimumab. High-dose corticosteroids successfully treated both conditions, though he never regained his baseline mental status. We review the literature on interstitial granulomatous dermatitis and encephalitis with immunotherapy.