HS dictionary


Red, sore bumps that often get larger, break open, and ooze pus.


Relating to a disease where the immune cells mistakenly attack healthy tissue in the body.


Long-lasting; continuing or occurring again and again for a long time.


Medical conditions that appear together.


Thin-walled, abnormal pocket or cavity that contains skin cells and fluid.


An abnormal connection or tunnel under the skin that can drain pus and forms because of injury, infection, or inflammation.


The recurrence or worsening of symptoms.

Hidradenitis suppurativa (HS)

(Hi-dra-den-i-tis • sup-per-uh-tee-vah) A chronic, systemic (throughout the body) inflammatory condition that may be caused by malfunctions in the body’s immune system. Symptoms include nodules and/or abscesses on the skin, as well as tracts or tunnels that can start to form between abscesses. These symptoms may be painful, leak pus, leave scars, and reappear after they’ve healed.

Hurley staging system

A well-accepted assessment of HS severity, which separates HS into three stages:

Stage I (mild): Usually shows up as one or more abscesses with no scarring or tunneling under the skin. Flares may clear up but then come back during any stage.

Stage II (moderate): Abscesses are widely spread and may become connected by tunnels. Tunnels (also known as tracts) can start forming deep in the skin, though they’re not always visible on the surface. Scars begin to form on the surface and within the deeper tissue.

Stage III (severe): Large areas of the body are covered by abscesses and scarring with widespread tunneling beneath the skin, connecting multiple abscesses.

Immune system

A network of cells, tissues, organs, and substances in the body that help fight disease, infection, and injury.


When the immune system sends cells to an area of the body in response to an irritant, as an attempt to protect itself from injury, disease, or further irritation.


An ulcer or sore on the skin, such as those caused by HS.


A small bump or lump under the skin that can become larger and inflamed over time.


Forcibly tearing or bursting through the skin.


A mark left on the skin or within the body where a wound, burn, or sore has not healed completely and connective tissue has developed.

Sinus tract

A narrow tunnel under the skin that is open on one end and lets fluid escape or drains fluid.


When the walls of an inflamed hair follicle rupture, leaking pus beneath the skin and forming a narrow opening or passageway extending from the wound underneath the skin, forming a connection between abscesses.