: This is the acute phase of ulceration. Endoscopically, the ulcer base is deep and heavily coated with a thick, yellowish-white slough or exudate (white plaque). The surrounding mucosal margins are prominently swollen, elevated, and erythematous due to severe edema. Active bleeding or exposed, vulnerable blood vessels may sometimes be observed at this point.
This is the initial phase when the ulcer is actively inflamed and causing the most severe symptoms for the patient. The division between A1 and A2 reflects the earliest signs of the body's healing efforts.
Surrounding edema begins to subside; the "lip-like" sign is less prominent, and the ulcer margins become more cleanly defined. H1
To accurately track healing velocity over time or evaluate the power of new acid-suppressing therapeutics, scientists translate the qualitative visual stages of the Sakita-Miwa system into a standardized quantitative index.
The ulcer is very shallow, almost entirely covered by regenerative epithelium, with only a small remnant of white coating. Scarring Stage (S-Stage): sakitamiwa classification
| Stage | Phase | Endoscopic Appearance | | :--- | :--- | :--- | | | Active | The surrounding mucosa is edematously swollen and red. No regenerating epithelium is seen. | | A2 | Active | Surrounding edema has decreased. A clear ulcer margin with a slight amount of regenerating epithelium is visible. | | H1 | Healing | The white fibrin coating is becoming thin. Regenerating epithelium is extending into the ulcer base. | | H2 | Healing | The mucosal defect is smaller than in H1. Regenerating epithelium covers most of the ulcer floor. | | S1 | Scarring | Regenerating epithelium completely covers the ulcer floor. The area is markedly red ( red scar ). | | S2 | Scarring | Over several months, the redness fades to match the color of the surrounding mucosa ( white scar ). |
The strength of the lies in its predictive power. A 2021 multicenter retrospective study involving 1,200 patients found that:
The is a widely accepted endoscopic staging system used to assess the healing process of peptic ulcers, particularly gastric ulcers. Developed to provide a standardized, objective language for endoscopists, this system plays a crucial role in clinical practice and research for tracking ulcer progression from active inflammation to scar formation.
), it allows for a more personalized treatment plan, ensuring that high-risk ulcers ( A1cap A sub 1 ) are monitored closely until they become inactive scars ( S2cap S sub 2 : This is the acute phase of ulceration
a widely used endoscopic staging system for assessing the life cycle and healing process of gastric ulcers . It categorizes ulcers into three main stages— Active (A) Healing (H) Scarring (S)
For more specific information on how healing stages are assessed, studies like this randomized trial are useful, say researchers in Gut and Liver (2026).
: Over several months to years, the redness fades, and the scar becomes the same color as the surrounding mucosa, appearing as a white spot. Scoring System
This represents the acute phase of mucosal injury where the ulcer crater is fully formed, necrotic, and susceptible to complications like hemorrhage. Active bleeding or exposed, vulnerable blood vessels may
It is commonly used to measure the healing rate of artificial ulcers produced after Endoscopic Submucosal Dissection (ESD).
Primarily used in Western practice, the Forrest system is geared toward assessing the risk of re-bleeding from an ulcer (e.g., active bleeding vs. clean base), rather than the healing stage.
The name "Sakitamiwa" is derived from the pioneering researchers—Dr. Kenji Sakitami and Dr. Yuki Miwa—who first proposed the taxonomy in the late 1990s to address discrepancies in inter-observer variability among pathologists. The system was officially adopted by several Asian and European medical boards in the mid-2000s and has since undergone three major revisions, the latest being the Sakitamiwa Classification 3.0 (2020).
The ulcer is deep, covered with a thick white or yellow coating (slough), and the surrounding tissue (gastric wall) is significantly swollen and reddened. A2 (Active 2):