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ORPHA:538863

Classic pyoderma gangrenosum

high confidenceSubtype of disorder

Also known as: Ulcerative pyoderma gangrenosum

Publications

101

52.7th percentile

Trials

2

Interventional, condition-specific

Researchers

487

Distinct authors in sample

Gene link

—

Readiness

2/6

Stages with a signal

Clinical definition (Orphanet)

A rare subtype of pyoderma gangrenosum disease characterized by rapidly , single or multiple, painful, aseptic ulcers which present overhanging, violaceous and undermined borders, surrounding induration and erythema, and granulation tissue (occasionally necrotic tissue and/or a purulent exudate) at the base, mainly affecting the legs (but other body surfaces may also be involved), leading to chronic ulcerations and often regressing with cribriform mutilating scars. The disease presents a chronic relapsing course and systemic features (e.g. fever, malaise, arthralgia, myalgia) may be associated.

How rare: How common this is has not been clearly measured.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

2/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    101 matched papers (72 in last 10 years) Source

  3. Phenotype characterisedNot found

    No HPO disease–phenotype associations via Monarch for these Mondo IDs

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  6. Interventional trialPresent

    2 matched on ClinicalTrials.gov (1 recruiting in sample)

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

Phenotypes (Monarch / HPO)

None returned for this Mondo ID. That often means “not linked under this ID,” not “no clinical features.”

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

Open Targets candidates

No drugs or clinical candidates returned for this Mondo ID on Open Targets.

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

Literature

Is anyone studying this?

101

101 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

101 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

72 in the last 10 years · high confidence · 52.7th percentile (publications denominator)

Phrase hits: 101 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

487

Distinct author names in 101 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Ortega-Loayza AG7 papers · 2024

    Department of Dermatology, Oregon Health & Science University, Portland, OR, USA.

    Papers in Europe PMC
  2. 02
    Alavi A4 papers · 2024

    Department of Medicine, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.

    Papers in Europe PMC
  3. 03
    Shinkai K4 papers · 2023

    Department of Dermatology, University of California, San Francisco, San Francisco, California. Electronic address: kanade.shinkai@ucsf.edu.

    Papers in Europe PMC
  4. 04
    Marzano AV3 papers · 2024

    Dermatology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Pace, 9, 20122, Milan, Italy. angelo.marzano@unimi.it.

    Papers in Europe PMC
  5. 05
    Maverakis E3 papers · 2018

    Department of Dermatology, University of California, Davis, Sacramento, CA, United States.

    Papers in Europe PMC
  6. 06
    Mostaghimi A3 papers · 2024

    Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.

    Papers in Europe PMC
  7. 07
    Nelson CA3 papers · 2023

    Department of Dermatology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia.

    Papers in Europe PMC
  8. 08
    Wang EA3 papers · 2022

    Department of Dermatology, University of California, Davis, Sacramento, CA, United States.

    Papers in Europe PMC
  9. 09
    Afifi L2 papers · 2020

    Department of Dermatology, University of California, San Francisco, San Francisco, California.

    Papers in Europe PMC
  10. 10
    Callen JP2 papers · 2024

    Division of Dermatology, Department of Medicine, University of Louisville, Louisville, Kentucky.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

2

interventional trials for this specific condition

2 interventional trials matched this specific condition name; 1 currently recruiting in our sample. 26 trials are registered for pyoderma gangrenosum, the broader category — shown separately because they may or may not enrol this specific subtype.

Data as of 11 September 2026

2 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 84.5th percentile).

high confidence · 84.5th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

2 interventional trials matched after quoted-phrase search and title/condition post-filter.

Broader category: pyoderma gangrenosum

26

Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.

Worth raising with a clinician. How we count trials.

Recruiting under the broader category

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 3 · after dedupe 3 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 3 · dropped 0 · fetched 2026-07-30

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Uncertain / not reviewed (3)

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Classic pyoderma gangrenosum — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

"Classic pyoderma gangrenosum" OR "Ulcerative pyoderma gangrenosum"

Run this search on Europe PMC

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Classic pyoderma gangrenosum" OR "Ulcerative pyoderma gangrenosum"

Interventional trials matched via: phrase (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 2 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.

Parent-category trials query:

"pyoderma gangrenosum"

Query health: ok — strategies attempted: phrase; with hits: phrase

Run this search on ClinicalTrials.gov

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-27T18:12:31.312Z