After diagnosing hidradenitis suppurativa (HS), a dermatologist or other doctor may classify each case of HS using the Hurley staging system. This is a severity staging system for HS symptoms with three distinct stages. The Hurley staging system was developed by a dermatologist in 1989.

Some people with mild hidradenitis suppurativa never progress to more advanced stages. However, some people’s HS symptoms can become increasingly severe if not treated. Early diagnosis and treatment can help prevent HS from becoming worse over time.

Hurley Stage 1 (Mild)

• Stage 1 hidradenitis suppurativa involves one lesion or isolated abscesses without sinus tract formation (narrow openings underneath the skin) or scarring. HS often begins as small pea-sized bumps that are sometimes mistaken for acne, boils, or ingrown hairs.
• The vast majority of people with HS — 68 percent — fall into the mild category.
• Stage 1 HS is the most easily treated stage and can often be treated with oral or topical medications.

Hurley Stage 2 (Moderate)

• Stage 2 is defined by recurring and often multiple abscesses with scarring and sinus tracts.
• Stage 2 is the second most common stage. It accounts for 28 percent of people with HS.
• Oral or topical medications are usually the first approach for treating stage 2 HS. Surgical procedures may be needed if medications are not effective.

Hurley Stage 3 (Severe)

• Stage 3 HS involves multiple lesions across an entire area of the body with interconnected sinus tract formations, scarring, and sometimes foul-smelling pus.
• Stage 3 accounts for a small percentage of HS cases. About 4 percent of people with HS are classified as stage 3.
• Stage 3 HS can be treated with oral retinoids, immunosuppressive medications, biologics, and surgery.

Some doctors also use a more detailed staging system called the Sartorius score to assess treatment outcomes. A Sartorius score considers which parts of the body are affected, the number and type of lesions, the distance between lesions, and the condition of the skin separating lesions. The Sartorius score is used more frequently in research settings than clinical practice.

Condition Guide

• Hidradenitis Suppurativa (HS) — An Overview
• Hidradenitis Suppurativa (HS) — The Path to Diagnosis
• Symptoms of Hidradenitis Suppurativa (HS)
• Treatments for Hidradenitis Suppurativa (HS)
• What Causes Hidradenitis Suppurativa (HS)?