Pemphigus is a group of rare autoimmune diseases that cause painful blisters and open sores on the skin and mucous membranes. It affects roughly 3 people per million worldwide each year, making it uncommon but serious. The immune system mistakenly produces antibodies that attack proteins holding skin cells together, causing the layers of skin to separate and blister.
What Happens Inside the Skin
Your skin cells are held together by small protein bridges called desmosomes, which act like rivets keeping a sheet of fabric from pulling apart. In pemphigus, the immune system produces antibodies (mostly a type called IgG4) that target specific proteins within these bridges. These proteins, known as desmogleins, come in two main forms. Which type the antibodies attack determines where blisters form and how severe the disease becomes.
When antibodies latch onto desmogleins, they interfere with the connections between skin cells and disrupt signaling pathways that normally keep cells anchored. The result is that cells in the upper layers of skin detach from each other, a process called acantholysis. Fluid fills the gaps, forming fragile blisters that rupture easily and leave raw, painful erosions.
Main Types of Pemphigus
Pemphigus Vulgaris
This is the most common form. It typically starts with sores inside the mouth, often on the gums, inner cheeks, or palate. These oral erosions can make eating and swallowing painful. Many people see a doctor initially thinking they have severe canker sores or a dental problem. Over time, flaccid (soft, easily broken) blisters may appear anywhere on the body. Some patients only ever develop mouth sores, while others progress to widespread skin involvement depending on which desmogleins their antibodies target.
Pemphigus Foliaceus
This form is more superficial, meaning blisters form in the outermost layer of skin. Because the blisters are so shallow, they break almost immediately and leave behind crusted, scaly erosions rather than intact blisters. It tends to start on the face, scalp, and upper chest before potentially spreading. A key difference from pemphigus vulgaris: it almost never affects the mouth or other mucous membranes.
Paraneoplastic Pemphigus
This is the rarest and most serious type, occurring in people who have an underlying cancer, most often a lymphoma or other blood cell malignancy. It causes severe mouth sores along with skin blistering. Diagnosis requires evidence of both the skin disease and an internal tumor, along with specific antibodies that target a different set of proteins. This form can also affect the lungs, which distinguishes it from the other types.
Who Gets Pemphigus
The global incidence of pemphigus vulgaris is about 2.83 cases per million people per year, with notable geographic variation. Southern Asia has the highest rates, at roughly 5 cases per million. Certain ethnic groups, particularly people of Ashkenazi Jewish, Mediterranean, and South Asian descent, are more frequently affected. Most cases are diagnosed between ages 40 and 60, though it can occur at any age. Both men and women are affected.
How Pemphigus Is Diagnosed
Diagnosis relies on three pillars: clinical appearance, a skin biopsy, and antibody testing. No single test alone confirms pemphigus.
During a physical exam, doctors often check for what’s called the Nikolsky sign. This involves pressing a finger sideways against the skin near a blister. In pemphigus, the top layers of skin slide away from the layers beneath, extending the blister into what appeared to be normal skin. A positive Nikolsky sign strongly suggests pemphigus, though it can also occur in a few other conditions like severe drug reactions.
A skin biopsy examined under a microscope shows the characteristic separation between skin cells. A second biopsy sample is tested with a technique called direct immunofluorescence, which uses fluorescent markers to reveal antibodies deposited between skin cells. This appears as a distinctive “chicken wire” pattern. Blood tests using ELISA technology can detect circulating antibodies against desmogleins with high accuracy. One study found ELISA detected untreated pemphigus foliaceus with 100% sensitivity and 98% specificity, though sensitivity dropped slightly in patients already receiving treatment.
Treatment Approach
Before modern treatments existed, pemphigus was frequently fatal. Today, the disease is manageable for most people, though treatment is long-term and requires careful monitoring.
The standard first-line approach combines two strategies: corticosteroids to quickly suppress the immune attack, and a targeted therapy called rituximab that depletes the specific immune cells producing the harmful antibodies. American and European guidelines recommend two infusions of rituximab given two weeks apart, alongside a tapering course of corticosteroids. The goal is to control the disease quickly with steroids, then reduce or stop them as rituximab takes full effect over several weeks.
Before rituximab became widely available, patients often needed high-dose steroids for months or years, along with other immune-suppressing medications. This carried significant risks. In a 12-year study from a major pemphigus center in Tehran, the overall mortality rate was 4.16%. Among those who died, 75% had been on high-dose steroids and traditional immunosuppressants, while only 25% had received rituximab-based treatment. The most common causes of death were infections, particularly pneumonia and sepsis, which are direct consequences of a suppressed immune system. Cardiovascular disease and gastrointestinal bleeding accounted for additional deaths.
Living With Pemphigus
Day-to-day management focuses on protecting fragile skin, preventing infections, and controlling pain. Open erosions are vulnerable to bacterial contamination, so gentle wound care is essential. Washing with mild soap, keeping wounds clean, and applying prescribed topical treatments can reduce the risk of infection and minimize scarring. If your mouth is involved, soft foods, avoiding spicy or acidic items, and using medicated mouth rinses can make eating more tolerable.
Most people with pemphigus go through cycles of flares and remission. Some eventually achieve long-term remission, particularly with rituximab-based regimens, while others need ongoing low-dose treatment to keep the disease quiet. Antibody levels in the blood often correlate with disease activity, so periodic blood tests help guide treatment decisions. A rising antibody level can signal a flare before new blisters appear, giving doctors a chance to adjust therapy early.
The emotional toll of pemphigus is real. Visible skin erosions, chronic pain, and the unpredictability of flares can affect quality of life significantly. Many patients benefit from connecting with support groups or mental health professionals experienced in chronic illness, alongside their dermatology care.