Hidradenitis suppurativa

Also called HS or Acne inversa

Hidradenitis suppurativa (HS) is a long-term skin condition that causes painful lumps, abscesses and scarring, usually in areas where skin rubs together, such as the armpits, groin, buttocks and under the breasts. It usually starts after puberty. It is not caused by poor hygiene and is not infectious.

Last updated Nov 9, 2026

What it is

Smoking and being overweight can make it worse.

Treatments include antiseptic washes, antibiotics, hormone treatments, biologic medicines and surgery for areas that keep coming back.

Common signs

  • Painful lumps that may fill with pus
  • Lumps that burst and leak
  • Tunnels under the skin
  • Scarring
  • Blackheads in pairs

How it is usually diagnosed

  • Examination of the skin
  • A swab, if infection is suspected

Records worth keeping

Keeping these together makes each appointment easier, especially when you see a new doctor:

  • Dermatology letters
  • Treatments tried and their effect
  • Photos of affected areas over time

Questions to ask your doctor

  • How severe is my HS?
  • Which treatments should I try next?
  • Would surgery help?

When to get help right away

Call 112 or go to the nearest emergency department if you have:

  • A lump with spreading redness, high fever or feeling very unwell: get urgent medical help

This page is general information. It is not a diagnosis and does not replace a doctor who knows your history. Medfold keeps your records organised; it does not interpret them.

Sources