A bulla is a Latin word that means "bubble or spike." Any spherical protrusion, especially a cystic one can be referred to as bulla. A bulla is a fluid-filled sac or bullous lesion that forms when fluid becomes trapped behind a thin layer of skin. It's a blister of some sort. The plural form of bulla is bullae. The blister must be greater than 0.5 centimeters (5 millimeters) in diameter to be categorized as a bulla. Vesicles are smaller blisters ie less than 5mm in diameter.
Blisters that become infected can be quite painful. If left untreated, they can be dangerous. Starting in your blister, a bacterial, viral, or fungal infection might spread to other parts of your body. Blisters usually rupture and heal in one to two weeks on their own. It is always recommended to avoid trauma or friction to the bullae during this healing phase.
Bullous skin disorders constitute an array of dermatoses, some of which can be fatal. Blisters and bullae in the skin and mucous membranes are the most common clinical characteristics, which result in skin and mucosal erosions when they rupture. When these bullae and erosions affect a large body surface area, the risk of dehydration, electrolyte imbalance, and infection increases along with it.
Pathogenic autoantibodies can be found in both the blood circulation and the skin lesions in autoimmune bullous skin diseases, while hereditary variables play a larger role in the pathogenesis of non-immune bullous skin diseases.
Based on the skin layer that is affected and where the bulla forms, bullous skin disorders can be broadly divided into intraepidermal and subepidermal bullous skin diseases. Pemphigus Vulgaris and bullous pemphigoid are the two most frequent autoimmune bullous skin diseases. Below is the classification of bullous dermatoses as autoimmune bullous dermatoses and non-autoimmune bullous dermatoses:
Autoimmune bullous dermatoses |
Non-autoimmune bullous dermatoses |
Pemphigus Vulgaris |
Epidermolysis bullosa simplex |
Bullous pemphigoid |
Hailey Hailey disease |
Pemphigus foliaceus |
Darier's disease |
Mucous membrane pemphigoid |
Epidermolysis bullosa dystrophica |
Cicatricial pemphigoid |
Bullous drug eruptions |
Dermatitis herpetiformis |
Friction blisters |
Linear IgA bullous dermatosis |
Thermal burns |
Epidermolysis bullosa acquisita |
Viral Infections |
Pemphigoid gestationis |
Staphylococcal Scalded skin syndrome |