To diagnose hidradenitis suppurativa (HS), a doctor will look at the physical appearance and location of painful bumps under your skin.

Hidradenitis suppurativa (HS) is a chronic skin condition that causes painful bumps under the skin in areas where skin rubs together. It has characteristics that set it apart from other skin conditions.

To diagnose HS, a doctor, often a dermatologist, will examine the location and appearance of your bumps and abscesses.

If one of the sores is leaking fluid, the doctor may swab it and take a sample to check for infection. However, this is not necessary to diagnose HS.

Read on to learn more about diagnosing HD and when to contact a doctor for help.

To diagnose hidradenitis suppurativa, the doctor will request your health history and ask about the location of any breakouts. The placement of bumps on your body is an indicator of HS.

They will examine any bumps or abscesses you currently have. HS has some physical traits that set it apart from boils, acne, or other similar-looking conditions.

The doctor looks for several characteristics before making a diagnosis of HS. These may include:

  • lesions consistent with HS
  • typical pattern of distribution
  • recurrence of breakouts

If one of your bumps is leaking fluid, the doctor may take a sample on a swab to test for infection. This is not a test for HS itself. There’s currently no lab test to determine the presence of the condition.

A few skin conditions can appear similar to HS. A trained doctor, like a dermatologist, knows how to tell the difference.


HS often begins with one or two nodules or bumps under the skin, which can resemble a skin infection.

Infection can produce the same type of swollen, red, tender bump or pus-filled abscess. The difference is that bacteria cause infections, while an overreaction of the body’s immune system causes HS when keratin and sweat build up inside a hair follicle, trapping bacteria.


Acne and HS can bear a close resemblance. Both begin when hair follicles become blocked by oil, keratin, dead skin cells, and bacteria. But HS occurs any place with sweat glands, while acne can occur anywhere on the body.

Unlike in most cases of acne, HS creates ropy tunnels under the skin between nodules called sinus tracts. These channels connect lesions and can scar over time,

Ingrown hair

Ingrown hairs occur when a hair curves and grows back into the skin, causing inflammation and a bump. For people with curly hair, this may be a particular problem in the beard and neck area, occurring in clusters.

Although they both appear as bumps on the skin, ingrown hairs differ from HS because hair piercing the skin from the outside and creating inflammation is the cause. Keratin, sweat, and bacteria blocking the hair follicle from underneath the skin cause HS.


Folliculitis is inflammation of the hair follicle. It commonly happens in follicles when they’re damaged, allowing bacteria to get inside. Less common causes include blockage or irritation of the follicle. Damage occurs due to:

  • frequently rubbing or touching the skin
  • wearing tight clothing
  • rubbing skin on skin
  • shaving

The bumps folliculitis causes may resemble HS but tend to be smaller and commonly resolve on their own, especially when triggers are avoided.

HS may begin to scar and can limit mobility, so early diagnosis and treatment are important.

A dermatologist is a specialist trained to recognize skin conditions. Your doctor may refer you to a dermatologist for specialized care.

Contact a doctor if the breakouts are:

  • painful
  • infected (look for pus or draining, swelling, crusting, pain, warmth, or a red streak)
  • blistering
  • spreading

If you think you have HS, you may have some questions. Here are answers to a few commonly asked questions.

Can a blood test detect hidradenitis suppurativa?

A blood test cannot detect or diagnose hidradenitis suppurativa. Currently, no lab tests are available to diagnose this condition, but a doctor may swab a sore that’s leaking to check for infection.

How is hidradenitis suppurativa treated?

A doctor will work with you to set up a treatment plan to help reduce inflammation and irritation. This may include:

Hidradenitis suppurativa is a chronic skin condition that causes painful, boil-like bumps to develop when hair follicles become blocked. It usually occurs in areas with many sweat glands and where skin rubs together.

A doctor can typically diagnose HS based on an oral history of the outbreaks and a visual inspection of the outbreak areas. How HS appears differs from acne, boils, or cysts, which lets doctors know this condition is present.

HS treatment includes a variety of methods, including skin care, medications, and surgical procedures. A doctor can discuss a treatment plan after a complete evaluation.