Bullous amyloidosis is a rare form of cutaneous involvement in systemic amyloidosis. It should be considered in a patient with an unexplained bullous eruption, especially if the patient is older or has other signs of amyloidosis.
Clinical features:
(1) The patient develops a bullous skin eruption which may be pruritic and/or hemorrhagic.
(2) Other types of skin lesions may also be present.
(3) The patient may have a history of amyloidosis but in some patients the skin lesions may be the first manifestation.
(4) The patient will have evidence of monoclonal proteins in serum and/or urine as well as elevation in free serum light chains.
A skin biopsy will show subepidermal bullae. Amyloid deposits are often seen in the papillary dermis on special histochemical stains or with immunofluorescence. A few patients have negative amyloid stains but the deposits can be seen on electron microscopy.
Differential diagnosis:
(1) cutaneous porphyria
(2) bullous pemphigoid
(3) drug eruption
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