A new eruption of bullous pemphigoid within psoriatic plaque
Now open: Certificate Course in Management of Covid-19 by Govt. Of Gujarat and PlexusMDKnow more...Now open: Certificate Course in Management of Covid-19 by Govt. Of Gujarat and PlexusMDKnow more...
A 64-year-old male with a history of hypertension and psoriasis treated with cyclosporine 200mg BID presented after blisters appeared on his bilateral upper extremities 2-3 days after running out of cyclosporine.

Two months before presentation, the patient experienced acute worsening of his psoriasis with diffuse erythema, plaques, scaling, fissuring in his hands and knees, and chills. Biopsy demonstrated erythrodermic psoriasis. Two weeks prior to presentation, he re-established care with dermatology and was started on cyclosporine 200mg BID (2.5-3mg/kg/day), triamcinolone 0.1% ointment BID to the body, and hydrocortisone 2.5% ointment BID to the face. He improved with 70% reduction in body surface area involvement. Three days prior to presentation, he ran out of cyclosporine. 56 hours after the last dose, he noted appearance of blisters on the upper extremities and presented to dermatology.

On examination, the patient had erythematous papules and scaling on his face and bilateral ears and generalized erythema and scaling of his bilateral arms. Multiple tense, fluid filled blisters were noted on his bilateral flexor forearms and outer upper arms, some appearing to follow the lines of his psoriatic plaques. Eroded and flaccid blisters were also noted on his bilateral palms and plantar feet at the bases of his toes. His bilateral lower legs were erythematous and edematous without fissures. His chest and abdomen were relatively spared with minimum erythema, though a lichenified plaque was noted on the central back.

Two biopsies were obtained of blisters on the dorsum of the left hand. H&E demonstrated subepidermal separation with eosinophils within the blister cavity and aligned along the adjacent dermal-epidermal junction (DEJ). Direct immunofluorescence revealed linear C3 deposition along the DEJ, consistent with a diagnosis of BP. Cyclosporine was re-initiated and then gradually tapered, and methotrexate was started and up-titrated to 17.5 – 20 mg/week for treatment of both psoriasis and BP. No new blisters were reported on this regimen, and psoriasis was stable.

Source: https://www.jaadcasereports.org/article/S2352-5126(20)30837-7/fulltext?rss=yes