Asboe-Hansen sign

Asboe-Hansen sign is a clinical dermatological sign that indicates the presence of increased dermal edema or fluid accumulation beneath the skin. This sign is particularly associated with certain skin conditions, such as bullous pemphigoid and pemphigus vulgaris, which are autoimmune blistering diseases. The Asboe-Hansen sign is characterized by the extension of a blister to an uninvolved area when pressure is applied to the top of an existing blister. This phenomenon is also known as the "blister spread sign" and is indicative of the fragility of the skin and the presence of fluid under pressure within the dermal layers.

Pathophysiology[edit | edit source]

The pathophysiology of the Asboe-Hansen sign involves the disruption of the normal adhesion between skin cells, specifically within the epidermis or between the epidermis and dermis. In conditions like bullous pemphigoid and pemphigus vulgaris, autoantibodies target proteins that are crucial for cell-cell adhesion within the skin. This leads to the formation of blisters as the skin layers separate due to weakened cell connections. The pressure applied during the test for the Asboe-Hansen sign forces the fluid within the blister to spread into adjacent, previously unaffected areas, demonstrating the presence of subepidermal or intraepidermal blisters and the overall fragility of the skin.

Clinical Significance[edit | edit source]

The Asboe-Hansen sign is an important diagnostic tool in dermatology. Its presence helps in the differentiation of blistering skin diseases, aiding in the diagnosis of conditions like bullous pemphigoid and pemphigus vulgaris. Identifying the sign is crucial for early diagnosis and treatment, as these conditions can lead to significant morbidity if left untreated. Treatment typically involves the use of immunosuppressive drugs to reduce the autoimmune response and prevent further blister formation.

Differential Diagnosis[edit | edit source]

While the Asboe-Hansen sign is most commonly associated with autoimmune blistering diseases, it is important to consider other potential causes of dermal edema and blister formation in the differential diagnosis. These can include allergic reactions, infections, and other dermatological conditions that may present with similar symptoms. A thorough clinical evaluation and additional diagnostic tests, such as biopsy and direct immunofluorescence, are necessary to confirm the diagnosis and rule out other potential causes.