People with hidradenitis suppurativa sometimes receive misdiagnosis for other conditions, including folliculitis and acne. A dermatologist can make an accurate diagnosis.

Hidradenitis suppurativa (HS) is an inflammatory skin condition. It causes painful lumps to form under the skin.

It’s not understood exactly what causes HS. The condition occurs when hair follicles fill with keratin, sweat, and bacteria and become blocked and inflamed. These lumps can burst open, which can lead to infection, and often leave scar tissue when they heal.

In early stages, HS looks like small red bumps on the skin. As it progresses, the buildup of bacteria can cause follicles to expand and join with each other. This can create tunnels under the skin, which can also spread infection and become very painful.

HS is often misdiagnosed, especially in the early stages. This leads to delays in proper treatment. People living with HS wait an average of 10 years between the onset of symptoms and diagnosis. Because of the delay in diagnosis, many people are diagnosed at a more severe stage of HS.

One of the reasons for the delay in getting a proper diagnosis is that HS can look like other skin issues. Scheduling an appointment with a dermatologist, a specialist in diagnosing and treating skin conditions, can help determine whether you’re dealing with HS or something else.

In the meantime, here are some conditions that may look similar to HS.

Acne vulgaris, usually just known as acne, is a common skin condition. Acne can be a combination of pimples, blackheads, whiteheads, and cysts.

Some people have skin that produces more sebum, the skin’s natural oil. This may make them more prone to acne. Acne occurs when pores fill with dead skin cells and sebum. When pores are blocked, they become inflamed, resulting in acne.

Early stages of HS can look like acne. Both conditions can cause small red bumps on the skin’s surface. But the location of the red bumps is often different in HS and acne.

Acne is most common on the face, back, chest, and shoulders. HS is more likely to happen in places where skin rubs against skin. Common sites of HS include the buttocks, breasts, underarms, and around the genitals.

HS is typically more painful than acne. Acne may cause some pain and swelling but usually not as much as HS. Poking and popping acne can cause some of the spots to burst, but they won’t typically burst open on their own. HS bumps get so inflamed that they often burst on their own.

Acne conglobata is a rare and more severe form of acne. As with the more common form of acne, with acne conglobata, pores fill with dead skin cells and oil and become inflamed.

In acne conglobata, inflammed pores expand below the surface. The inflamed pores join with each other, spreading inflammation and infection. This is similar to how infection spreads in HS.

Acne conglobata and HS look very similar. Both conditions can cause significant scarring. This explains why acne conglobata is one of the top misdiagnoses for HS.

Acne conglobata is often diagnosed based on personal medical history. It’s more likely to develop in someone who is using anabolic steroids or taking thyroid medication or those who’ve had androgen-producing tumors or exposure to halogenated aromatic hydrocarbons.

HS and acne conglobata can affect some of the same sites, but there are also differences. Acne conglobata typically affects the face, chest, shoulders, thighs, and upper arms. Both acne conglobata and HS can be present on the buttocks, but HS is more likely to occur where skin rubs together.

A cyst is a lump on your skin that is filled with yellow or white fluid and debris. It commonly appears on the face, back, trunk, or scalp, but can sometimes occur in other areas as well.

Cysts can be caused by different things. They can be a part of HS but there are other reasons you may get a cyst.

In many cases, cysts occur after an injury or surgery. Sometimes it’s an effect of acne. In other cases, cysts show up with no obvious cause.

Cysts aren’t harmful, but they can cause discomfort or pain. Cysts may burst and then grow again, typically in the same site, though they don’t always come back. If the cyst is related to HS, it’s more likely to spread after it bursts.

The average cyst grows slowly. HS can grow and spread quickly.

Ingrown hairs happen when a hair curls back down into the follicle instead of growing out. Follicles blocked by ingrown hairs can be red and itchy. Sometimes you can see a bit of pus or the hair trapped inside.

Ingrown hairs are most likely to happen after hair removal, like waxing or shaving. They’re also more common if your hair is thick or curly. You might get multiple ingrown hairs in the same area after hair removal, as the hair starts growing back.

Ingrown hairs don’t usually need treatment and resolve on their own. HS lumps typically grow bigger and spread.

Folliculitis occurs when a hair follicle becomes infected or inflamed, leading to a bump or pustule. This can occur when the hair follicle is damaged, commonly as a result of:

  • wearing tight clothing
  • shaving
  • waxing
  • being in a hot tub

Damage to the hair follicle makes it more prone to infection.

The early stage of folliculitis looks like small, red, inflamed spots. It may feel itchy or painful, or you may not feel anything. Early HS is more likely to be a lump under the skin or small, tender bumps.

Folliculitis can happen anywhere you have hair follicles, which is most of your body. It often goes away on its own within a few weeks. If not, the infection can spread, making the red bumps larger and filled with pus.

Meanwhile, HS typically doesn’t go away on its own without treatment.

Boils are pus-filled skin infections that occur around a hair follicle or oil gland. They typically appear red or purple and swollen.

A boil starts when a cluster of hair follicles and the skin around them get infected by bacteria such as Staphylococcus aureus. Damage to the skin from a bite or injury can make you more likely to develop a boil in that spot.

HS can cause boils, but not all boils are a result of HS.

Boils are most likely to happen on your neck, face, buttocks, and thighs. Several of these places are also common sites for HS.

Boils can also grow until they burst and can spread infection. With HS, as the condition progresses, multiple boils can grow and swell until they connect. This can create tunnels under the skin that spread the infection. Boils that are not part of HS are less likely to spread the same way.

Sometimes a boil resolves with no treatment needed. Other times, it keeps coming back and needs treatment to prevent it from forming again.

Hidradenitis suppurativa is a skin condition that’s often misdiagnosed. This can be frustrating and time-consuming. It also means that many people are at a more severe stage of HS by the time it’s diagnosed.

A dermatologist is a doctor who specializes in skin care. They’re the best person to make the right diagnosis and determine the best course of treatment.

If you’re being treated for a skin condition but it’s not getting better, reconnect with your dermatologist. If it’s HS, getting the right diagnosis sooner can help prevent it from progressing and improve your quality of life.