About this article
Medically reviewed- Written by
- Dr Han Simpson
- Medically reviewed by
- Dr Han Simpson
- Published
- August 21, 2026
- Medical review date
- September 8, 2026
- Evidence searched through
- September 8, 2026
- Next review due
- September 8, 2027
- Intended audience
- General Readers & Patients
- Geographic scope
- Worldwide
- Conflicts of interest
- None declared.
- Funding
- Website Owner
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- Report an error or editorial concern
- Medical disclaimer
- Read the medical disclaimer
The author also completed the medical check; this was not an independent review.
Bullous pemphigoid is a rare autoimmune skin disease that causes intense itching, a raised rash and, often, large tense blisters. It mainly affects older adults, is not contagious, and cannot be confirmed from a picture alone. New widespread blisters, broken skin or signs of infection deserve prompt medical assessment because early treatment can reduce new blister formation and protect the skin.
The immune system mistakenly targets proteins that help attach the outer skin layer (epidermis) to the deeper layer (dermis). Inflammation weakens that junction, allowing fluid to collect beneath the epidermis. This deeper split is why the blisters are often firm or “tense” rather than soft and easily collapsed.
What is bullous pemphigoid?
Bullous pemphigoid is an autoimmune subepidermal blistering disorder. “Autoimmune” means the immune system reacts against the body’s own tissue; “subepidermal” describes the level at which the blister forms. The condition is long-lasting but variable: symptoms may flare, settle and recur over months or years. Treatment aims for disease control and remission, not an instant cure.
It is most common after age 60 and especially in later life, although younger people can develop it. It does not spread through touch, shared towels, food or air. The NHS bullous pemphigoid guide notes that it may be serious but usually responds to treatment.
Bullous pemphigoid symptoms: what does it look like?
The earliest symptom is often persistent, sometimes severe itch. A person may have itchy skin for days or weeks before an obvious blister appears. The pre-blister rash can resemble eczema or hives, with raised patches, welts or small bumps. Some people have itch and inflamed skin without ever developing classic large blisters.
When blisters occur, common clues include:
- round or irregular fluid-filled blisters that feel firm or tight;
- clear, cloudy, yellowish or occasionally blood-stained blister fluid;
- itching that may be more prominent than pain;
- crusted, raw areas after a blister opens;
- new blisters appearing while older areas heal; and
- darker or lighter marks remaining temporarily after inflammation settles.
Typical sites include the arms, armpits, lower abdomen, groin, thighs and the fronts or inner surfaces of limbs. It can be localized or widespread. Mouth blisters can occur but are less common than in some other autoimmune blistering diseases. Skin redness may be subtle on brown or black skin, so warmth, swelling, pain, drainage and change from the person’s normal skin colour also matter.
Images and illustrations can explain patterns, but they cannot diagnose bullous pemphigoid. Blisters may look different depending on their age, treatment, skin tone and whether they have been scratched or infected. A clinician must consider the history, examination and specialized tests.
What causes bullous pemphigoid?
The immediate cause is an immune reaction against structural proteins at the basement membrane zone, especially BP180 and BP230. These proteins help anchor the epidermis to the dermis. Antibodies and inflammatory cells disrupt this attachment, creating a blister beneath the epidermis. The reaction is not caused by poor hygiene, an allergy to another person or an infection that can be passed on.
Why the immune reaction begins is often unclear. Age is the strongest background factor. Bullous pemphigoid is also seen more often in people with certain neurological conditions, but an association does not mean one disease directly caused the other. Physical injury, surgery, radiation, ultraviolet treatment or an infection may precede onset in some people.
Can a medicine trigger it?
Some medicines have been associated with bullous pemphigoid, including certain diabetes medicines called DPP-4 inhibitors (“gliptins”), some cancer immunotherapies, diuretics and several other drug groups. This does not mean a medicine is responsible in every case. Do not stop a prescribed drug suddenly. Ask the prescribing clinician and dermatologist to review when each medicine started, its benefits, alternatives and whether the timing fits the skin symptoms.
Conditions that can look similar
Many problems cause itching or blisters. The distinction matters because treatment differs:
- Pemphigus vulgaris more often produces fragile blisters that break easily and commonly affects the mouth.
- Contact dermatitis usually follows an exposure pattern and may cause small itchy blisters, oozing or sharply outlined inflammation.
- Shingles often causes pain, sensitivity and grouped blisters in a one-sided band.
- Drug eruptions can range from mild widespread rashes to dangerous skin reactions; a new medicine and systemic symptoms are important clues.
- Infection, insect reactions, eczema and hives can also mimic parts of the early presentation.
Our visual guide to hives versus other rashes can help explain why transient welts differ from fixed blistering lesions. If symptoms began after an antibiotic or another new medicine, the FMJ guide to Bactrim rash patterns and warning signs also illustrates why medication timing and urgent red flags must be reviewed. Neither guide replaces an examination.
How bullous pemphigoid is diagnosed
A dermatologist usually asks when the itch and rash began, how quickly blisters appeared, which body areas and mucous membranes are involved, and whether symptoms interrupt sleep or daily care. The clinician reviews medicines, recent treatments and health conditions, then examines both intact blisters and nearby skin for infection and distribution.
Confirmation commonly requires skin biopsies. One small sample may be taken from the edge of a fresh blister for routine microscopy. A second sample is often taken from nearby, apparently intact skin for direct immunofluorescence, which looks for the characteristic pattern of immune deposits along the basement membrane. Blood tests for antibodies such as BP180 or BP230 may support diagnosis and sometimes help with monitoring, but results must be interpreted with the clinical findings.
The DermNet clinical overview describes the combination of a subepidermal split, inflammation and antibody deposition used to confirm the condition. A biopsy is a brief procedure under local anaesthetic, but the exact number and site of samples depend on the presentation.
When to seek urgent medical care
Contact a clinician promptly for a persistent unexplained itchy rash, recurrent blisters, large painful blisters, mouth sores or any new blistering after starting a medicine. Same-day or urgent assessment becomes more important when skin is opening or symptoms are spreading.
Seek urgent medical care now if there are many rapidly spreading or leaking blisters, extensive raw skin, severe pain, eye symptoms, difficulty swallowing or breathing, dehydration, confusion, fever, or a person feels very unwell. Hot, swollen, increasingly painful skin, pus, foul drainage or rapidly expanding colour change may indicate infection. These signs can be harder to see on darker skin, so also pay attention to heat, tenderness and swelling.
Bullous pemphigoid treatment
Treatment is individualized according to blister extent, itch, frailty, other illnesses, medicines and the practical ability to apply creams or manage dressings. The goals are to stop new blisters, heal open areas, relieve itch and pain, treat infection when present, and minimize treatment harms.
Corticosteroids
Very potent topical corticosteroids are a common first treatment, especially when disease is limited or cream can be applied safely. They reduce skin inflammation and new blister formation. Widespread or difficult disease may require an oral corticosteroid. Because tablets can cause infection risk, high blood pressure, high blood sugar, bone thinning, eye problems and other effects, clinicians aim for the lowest effective exposure and monitor closely.
Other anti-inflammatory, immune-targeted and biologic treatments
Doxycycline or another anti-inflammatory option may be considered in some cases. Steroid-sparing immune medicines may be used when corticosteroids are insufficient or cause unacceptable effects. Biologic treatment is another option for selected patients. Choice varies by country, current approvals, disease severity and a person’s medical history, so a specialist must weigh benefits, interactions, monitoring and access.
The American Academy of Dermatology diagnosis and treatment guide explains that personalized plans can include corticosteroids, antibiotics used for anti-inflammatory effects, biologics and other immune-calming medicines. Never borrow another person’s cream or change a dose without the treating clinician.
Wound care and infection prevention
Do not deliberately pop intact blisters. If a clinician drains a large blister, the blister roof may be left in place as a natural cover. Wash hands before and after care, follow the wound-cleaning plan, and use non-stick dressings when advised. Loose, soft clothing and protection from friction can reduce accidental rupture. Ask how to bathe, which moisturizers or cleansers to use, and what drainage or odour should trigger review.
Monitoring and living with the condition
Follow-up is important even when the skin looks better. Clinicians may record the number of new blisters, affected body sites, itch severity, healing, infection and quality-of-life effects. Blood pressure, blood sugar, blood counts, kidney or liver tests and bone protection may be relevant depending on treatment. Report fever, new weakness, swelling, unusual bruising, vision changes, severe stomach symptoms or other suspected medicine effects promptly.
Keep an up-to-date medicine list and, if practical, dated photographs of change over time. Avoid scratching by keeping nails short and discussing safe itch control. Ask for help if dressings are difficult to reach or apply. Bullous pemphigoid can disrupt sleep and independence; practical support from family, community nursing or a wound-care service may be as important as the prescription.
Outlook
The course varies. Many people eventually achieve good control or remission, but treatment and monitoring may be needed for months or years, and relapse can occur. Healing usually does not cause deep scars, although temporary colour change is common. Widespread disease, infection and treatment side effects create greater risk, particularly in frail older adults, which is why an individualized plan and early review of complications matter.
Frequently asked questions
Is bullous pemphigoid contagious?
No. It is an autoimmune disease, not an infection passed between people. Open skin can become secondarily infected, but the underlying disorder itself does not spread by contact.
Does bullous pemphigoid always cause blisters?
No. Some people initially have persistent itch, eczema-like patches or hive-like welts, and a minority may not develop classic blisters. Testing can still identify the disease when the pattern is unclear.
Can bullous pemphigoid be diagnosed from a photo?
No. Photos can show useful clues but cannot confirm the level of skin separation or immune-deposit pattern. A dermatologist often needs one or more skin biopsies and may order blood tests.
Should I pop a bullous pemphigoid blister?
Do not pop it yourself. A clinician may safely drain a very large or uncomfortable blister while preserving its roof, then advise a dressing plan. Get prompt help if it opens, leaks heavily or looks infected.
What foods should be avoided?
There is no universal bullous pemphigoid diet. Mouth sores may make soft, bland foods easier temporarily. Nutrition advice should reflect diabetes, steroid use, swallowing ability and other health needs.
Can I stop treatment when the blisters disappear?
Not without medical advice. Treatment is often tapered gradually after disease control. Stopping suddenly can cause relapse and, for systemic corticosteroids, can be medically dangerous.
Key takeaway
Bullous pemphigoid commonly starts with intense itch and a raised rash, followed by firm fluid-filled blisters in many—but not all—people. It is autoimmune and not contagious. Because look-alike conditions require different care, diagnosis usually depends on specialist examination and skin biopsy testing. Prompt, individualized treatment can control inflammation, protect the skin and reduce complications; urgent medical care is needed for widespread open skin, infection signs, major mouth or eye involvement, or systemic illness.