Overview
Classic pyoderma gangrenosum (PG) is a rare and painful skin condition that causes deep, open sores (ulcers) to form on the skin. These ulcers are not caused by an infection, even though they can look infected. Instead, the immune system mistakenly attacks the skin, causing severe inflammation and tissue breakdown. The sores most often appear on the legs, but they can develop anywhere on the body. They typically start as small, red bumps or blisters that quickly grow into large, painful wounds with irregular, purple-colored edges. One of the most important features of classic pyoderma gangrenosum is a phenomenon called 'pathergy' — this means that even minor skin injuries, like a small cut or a needle prick, can trigger a new ulcer to form. This makes wound care and surgery especially tricky. The condition is also known simply as 'PG' and is sometimes grouped under the term 'neutrophilic dermatoses,' a family of conditions where white blood cells called neutrophils cause skin damage. Treatment focuses on calming the overactive immune system and helping wounds heal. Doctors commonly use steroid medications like prednisone, or stronger immune-suppressing drugs such as cyclosporine or dapsone. Wound care is also a critical part of management. Many patients experience flares and remissions over time. While there is no cure, most people can achieve good control of the disease with the right treatment plan.
Also known as:
Key symptoms:
Large, painful open sores (ulcers) on the skinUlcers with irregular, raised, purple or blue-colored edgesSores that grow quickly over daysSkin that breaks down after minor injuries or traumaIntense pain at the wound site, often out of proportion to the wound sizeRedness and swelling around the ulcerPus or discharge from the woundFever and feeling generally unwell during flaresScarring after ulcers healNew ulcers forming at sites of skin injury (pathergy)Sores most commonly on the lower legs, but can appear anywhere
Multifactorial
Caused by a mix of several genes and environmental factors
Adult
Begins in adulthood (age 18 or older)
FDA & Trial Timeline
4 eventsGuangdong Hengrui Pharmaceutical Co., Ltd — PHASE2
Shandong First Medical University — PHASE2
Boehringer Ingelheim — PHASE3
Oregon Health and Science University — PHASE2
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Classic pyoderma gangrenosum.
2 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Classic pyoderma gangrenosum.
Community
No community posts yet. Be the first to share your experience with Classic pyoderma gangrenosum.
Start the conversation →Latest news about Classic pyoderma gangrenosum
Disease timeline:
New recruiting trial: A Study to Test Whether Spesolimab Helps People With a Skin Condition Called Pyoderma Gangrenosum
A new clinical trial is recruiting patients for Classic pyoderma gangrenosum
New recruiting trial: Guselkumab in the Treatment of Adults With Pyoderma Gangrenosum (PG)
A new clinical trial is recruiting patients for Classic pyoderma gangrenosum
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What tests do I need to find out if I have an underlying condition like inflammatory bowel disease or a blood disorder?,Which treatment do you recommend for me, and what are the main side effects I should watch for?,How should I care for my wounds at home, and what should I avoid doing to prevent new ulcers?,What are the warning signs that my condition is getting worse and I need to seek urgent care?,Are there clinical trials or newer treatments I might be eligible for?,How will we know if my treatment is working, and how long before I should expect to see improvement?,Should I see any other specialists, such as a rheumatologist or gastroenterologist?
Common questions about Classic pyoderma gangrenosum
What is Classic pyoderma gangrenosum?
Classic pyoderma gangrenosum (PG) is a rare and painful skin condition that causes deep, open sores (ulcers) to form on the skin. These ulcers are not caused by an infection, even though they can look infected. Instead, the immune system mistakenly attacks the skin, causing severe inflammation and tissue breakdown. The sores most often appear on the legs, but they can develop anywhere on the body. They typically start as small, red bumps or blisters that quickly grow into large, painful wounds with irregular, purple-colored edges. One of the most important features of classic pyoderma gangren
How is Classic pyoderma gangrenosum inherited?
Classic pyoderma gangrenosum follows a multifactorial inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Classic pyoderma gangrenosum typically begin?
Typical onset of Classic pyoderma gangrenosum is adult. Age of onset can vary across affected individuals.
Are there clinical trials for Classic pyoderma gangrenosum?
Yes — 2 recruiting clinical trials are currently listed for Classic pyoderma gangrenosum on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Classic pyoderma gangrenosum?
10 specialists and care centers treating Classic pyoderma gangrenosum are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.