Refractory chronic spontaneous urticaria after heterologous COVID-19 booster vaccination.

Chronic spontaneous urticaria (CSU) involves recurrent, pruritic wheals lasting more than 6 weeks in response to various etiologies, including unknown causality. Though most cutaneous reactions to the COVID-19 vaccine series are self-limited and of short duration, more complex presentations including chronic spontaneous urticaria have been described. To the best of our knowledge, this is the first report of chronic spontaneous urticaria following heterologous mRNA COVID-19 booster vaccination that includes vaccination with both forms of the mRNA vaccine. Our patient received Pfizer-BioNTech for the primary series and Moderna for the booster. After failing several therapies, our patient's urticaria was refractory even to omalizumab. The source for chronic spontaneous urticaria development in our patient may be related to the unique humoral response elicited by receipt of a different mRNA vaccine manufacturer.

Ibrutinib skin toxicities: Report of two cases.

Ibrutinib is a Bruton tyrosine kinase inhibitor used to treat many hematologic conditions, most commonly B-cell lymphomas and leukemias. Reportedly, skin rash is an adverse event in up to 27% of treated patients. Histopathologic description of these lesions is limited. We present two cases of ibrutinib-associated skin toxicities showing diverse histopathologic features. Case 1: A 72-year-old man was started on ibrutinib for chronic lymphocytic leukemia. Two months later, he developed multiple erythematous crusted papules on the chest, abdomen, and extremities. Biopsies revealed varied histopathology including poorly formed granulomatous dermatitis, epidermal necrosis, ulceration, and panniculitis. Ibrutinib was discontinued and his skin lesions resolved within 1 month. Case 2: A 48-year-old man received ibrutinib after failing standard therapy for primary central nervous system EBV positive diffuse large B-cell lymphoma. Two months after initiation of ibrutinib, he developed multiple firm, red, non-tender nodules on the forehead, buttock, and thigh. Biopsies revealed "pseudolymphoma"-like reaction with dense pandermal lymphohistiocytic inflammation and granulomas. His skin toxicity resolved without cessation of therapy. Awareness of the spectrum of histopathologic features that may be encountered in skin lesions of patients treated with ibrutinib, as illustrated by these two cases, will be critical for optimal patient management.