Bulla

Bulla

A bulla (plural: bullae) is a large blister that is filled with fluid and is greater than 5 millimeters in diameter. Bullae are a type of blister and can occur in various conditions affecting the skin and mucous membranes.

Etiology

Bullae can form due to a variety of causes, including:

• Burns
• Friction
• Infections such as herpes simplex virus or varicella zoster virus
• Autoimmune diseases like pemphigus vulgaris and bullous pemphigoid
• Allergic reactions
• Genetic disorders such as epidermolysis bullosa

Pathophysiology

The formation of a bulla involves the separation of the epidermis from the dermis, or within the epidermis itself, leading to the accumulation of fluid. This fluid can be serous, serosanguinous, or purulent, depending on the underlying cause.

Clinical Presentation

Bullae are typically characterized by:

• A raised, fluid-filled lesion
• Diameter greater than 5 mm
• May be painful or itchy
• Can occur on any part of the body

Diagnosis

Diagnosis of bullae involves:

• Clinical examination
• Skin biopsy for histopathological analysis
• Direct immunofluorescence to detect autoimmune conditions
• Viral cultures or PCR for infectious causes

Treatment

The treatment of bullae depends on the underlying cause:

• For infectious causes, appropriate antiviral or antibiotic therapy
• For autoimmune conditions, corticosteroids and other immunosuppressive agents
• For symptomatic relief, topical treatments and pain management

Prognosis

The prognosis of bullae varies widely depending on the etiology. Infectious bullae may resolve with appropriate treatment, while autoimmune bullae may require long-term management.

See Also

• Blister
• Pemphigus
• Bullous pemphigoid

References

• James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: Clinical Dermatology. Saunders Elsevier.
• Bolognia, Jean L.; Jorizzo, Joseph L.; et al. (2008). Dermatology. Mosby.