Pemphigus

Question 1

Define pemphigus.

Answer 1

Pemphigus encompasses a group of potentially life-threatening autoimmune bullous diseases characterised by blisters and erosions of the mucous membranes and skin.

• Pemphigus vulgaris (PV) is the most common variant and affects skin and mucosa.
• Pemphigus foliaceus (PF) is confined to the skin.
• Paraneoplastic pemphigus (PNP) is rare; it can involve the skin and mucosal surfaces of the eyes, mouth, nasopharynx, and oesophagus.

Question 2

What is the aetiology of pemphigus?

Answer 2

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune, blistering skin diseases that are antibody mediated. PV accounts for 80% of cases of pemphigus, and PF accounts for 10%.

Paraneoplastic pemphigus (PNP) is both autoimmune (antibody-mediated) and cell-mediated. Pemphigus erythematosus and IgA pemphigus are rare variants.

Question 3

What are risk factors for pemphigus?

Answer 3

Increasing age

HLA DR4 (PV)

HLA DQ1 (PV)

HLA DRB1 (PNP)

Associated malignancy (PNP)

Question 4

Summarise the epidemiology of pemphigus.

Answer 4

Pemphigus is rare and, in the US, occurs with an overall incidence estimated as 4.2 new cases per million per year.

Most patients who develop pemphigus vulgaris, the most frequently occurring form of pemphigus, are aged >40 years.

Question 5

What are the signs and symptoms of pemphigus?

Answer 5

Chronic erosive blistering of the skin, mucosa, or both

Chronic mouth erosions (PV, PNP)

Painful lips (PNP)

Shortness of breath (PNP)

Pruritic scalp (PV, PF)

Bloody nose (PV, PNP)

Painful skin (PV, PF, PNP)

Question 6

What are investigations for pemphigus?

Answer 6

Skin biopsy, haematoxylin and eosin stain

Skin biopsy, direct immunofluorescence

Question 7

What is the management for pemphigus?

Answer 7

Oral corticosteroid
Rituximab

Question 8

What are the complications associated with pemphigus?

Answer 8

Volume depletion

Infection

Pain

Malignancy

Respiratory failure

Conjunctival scarring

Steroid-induced osteoporosis

Skin dyspigmentation

Question 9

What is the prognosis for pemphigus?

Answer 9

The outlook for patients with PV and PF is good if the disease is adequately controlled. There are cases of spontaneous remission, but most patients require some form of long-term immunosuppression.

Rituximab induces complete remission off therapy in 90% of patients.