What is pemphigus?
Pemphigus is a rare blistering disease. Patients are usually of middle age. The blisters can occur on the skin and on the mucous membranes, such as the lining of the mouth, and pemphigus is often accompanied by itch. Three kinds are distinguished: pemphigus vulgaris (the most common), pemphigus foliaceus, and paraneoplastic pemphigus (a form seen in patients with cancer).
How does it develop?
Pemphigus arises from an autoimmune reaction — a reaction of the body against its own tissue. In pemphigus this reaction is directed against certain components of the epidermis, so the epidermis detaches locally and forms blisters. Why the autoimmune reaction arises is not yet known; in some cases it is caused by medicines (penicillamine, captopril). In pemphigus vulgaris the blisters are fairly slack and fluid-filled and break easily on knocks or scratching. In pemphigus foliaceus the blisters are very slack and break very quickly, so superficial wounds (erosions) soon develop.
How is pemphigus treated?
Untreated pemphigus vulgaris is a life-threatening condition; pemphigus foliaceus has a much more favourable course untreated. Since the discovery of prednisone, however, pemphigus is very treatable: prednisone suppresses the autoimmune reaction so the epidermis stays intact. Prednisone is usually combined with azathioprine (which also lowers immunity) so the prednisone dose does not have to be too high. Treatment usually starts with a relatively high prednisone dose, and once no new blisters form the dose is lowered step by step.
For pemphigus vulgaris: prednisone combined with azathioprine, or prednisone alone; if this does not work, other immune-suppressing options. For pemphigus foliaceus: topical corticosteroids, or prednisone (with azathioprine). For pemphigus of the mouth: topical corticosteroids (special preparations for the mouth), and lidocaine locally for pain on eating.
What is the outlook?
The aim of treatment is to lower the daily amount of prednisone and azathioprine step by step without new blisters forming. Often it is possible to stop the medicines completely over time, though sometimes a low “maintenance dose” of prednisone and/or azathioprine is needed to keep the pemphigus under control.
When to see a doctor
See a doctor promptly for recurring blisters or non-healing erosions of the skin or mouth, as pemphigus needs specialist treatment and can be serious if untreated.