pyoderma gangrenosum bullous pyoderma gangrenosum https://www.malacards.org/card/bullous_pyoderma_gangrenosum MEDGEN:590609 A rare subtype of pyoderma gangrenosum disease characterized by grouped vesicles that rapidly spread and coalesce to form large bullae, which evolve into ulcerations that have an erythematous peripheral halo and central necrosis, mainly affecting the upper limbs and face. Lymphoproliferative diseases are frequently associated, thus prognosis is often compromised. UMLS:C0406687 Phemphigoid pyoderma gangrenosum MONDO:0035237 GARD:0022222 Orphanet:538869