A rare form of vasculitis presenting as chronic, persistent, firm, red-to-violaceous papules and nodules, typically over extensor surfaces and joints.
Characterized by classic 'target' lesions, often on the extremities, and is not associated with the neutrophilia and dermal infiltrate of Sweet's syndrome.
A well-demarcated, dusky red plaque that recurs in the exact same location upon re-exposure to the offending drug.
Can be bullous and edematous, but is typically pruritic and localized to the site of the bite, lacking the systemic fever and neutrophilia of Sweet's.
Presents as erythematous papules and plaques, often in chemotherapy patients, but histologically shows a neutrophilic infiltrate specifically around eccrine sweat glands.
Presents as a painful ulcer with a characteristic violaceous, undermined border, not the edematous plaques of Sweet's syndrome.
Presents as erythematous papules, plaques, or vesicles in patients with rheumatoid arthritis, and can be histologically similar but is tied to the underlying RA.
Presents as photosensitive, annular or papulosquamous plaques and is associated with positive Ro/SSA antibodies.
Lesions resemble urticaria but last longer than 24 hours, may be painful, and leave behind purpura; biopsy shows leukocytoclastic vasculitis.
Also known as eosinophilic cellulitis, it presents as edematous, cellulitis-like plaques, but biopsy reveals a dense eosinophilic infiltrate, not neutrophilic.
