What Is Panniculitis?

Learn About Causes, Symptoms, Treatments, and More

Panniculitis on the legs
James Heilman, MD/Wikimedia Commons/CC-BY-SA-3.

Panniculitis is a catch-all term used to describe inflammation of the fatty layer underneath the skin's surface. It causes inflamed lumps and plaques (broad, raised areas) on the skin which range in size from several millimeters to several inches across. In the majority of cases these lumps are painful.

Humans have three main layers of skin: the epidermis, the dermis, and subcutaneous tissue. The epidermis is the uppermost layer of skin, the layer we see every day.

The dermis is just below and holds our oil glands, sweat glands, hair follicle, and bulb. The deepest layer, the subcutaneous tissue, is the layer that protects our body.

Anyone, at any age, can develop panniculitis, but it tends to be more common in women.

Symptoms

The most notable indicator of panniculitis are tender lumps underneath the skin. You may have just one lump or a cluster of them. They may feel like knots or bumps under the skin, or they may be more broad, raised swellings called plaques. Sometimes the swellings drain oily fluid or pus.

The most common place for panniculitis to occur is on the lower legs (shins and calves) and feet. It can develop on other areas of the body, including the hands and arms, thighs, buttocks, abdomen, breasts, or face. It's much less frequently found in those areas, though.

You may also have a fever and feel run-down or fatigued. Aching in your joints or muscles, stomach pain, and nausea or vomiting can sometimes happen too.

These symptoms can sometimes appear even before the swellings do.

Panniculitis also can cause dark discolorations on the skin that look quite like bruising. These typically will fade over time, once the inflammation recedes. In some cases, it can also leave depressed areas on the skin. This happens if the tissue beneath has be destroyed.

These depressed areas may improve with time but often they’re permanent.

Causes

Panniculitis isn’t caused by any one specific condition; rather, many conditions can cause inflammation of the subcutaneous tissue. It may take some sleuthing to determine exactly what is causing your panniculitis.

Infection is likely the most common cause of panniculitis. Bacteria, viruses, fungi, even parasites, can trigger panniculitus development. And we aren't just talking infection involving the skin tissue. Having an infection like strep throat or tuberculosis can cause panniculitis to occur.

Injury to the skin, either by trauma or cold, can also cause panniculitis. This is more likely to happen in areas with lots of fatty tissue, like the breast or buttock. It doesn't always have to be a hard blow to the area either. Something as simple as an injection could do it. Very cold temperatures can cause panniculitis in exposed skin (called, quite obviously, cold panniculitis).

Certain medications can also trigger its development. Some of the bigger offenders are sulfonamide antibiotics, birth control pills and estrogen, and large doses of corticosteroids.

Other causes of panniculitis can include:

In many cases, a specific cause isn’t identified. This is called idiopathic panniculitis.

Diagnosis

Panniculitis can be diagnosed by a visual inspection. A biopsy is often done to confirm the physician’s assessment. Your doctor may also swab your throat to check for infections like strep, and may even do a chest x-ray to look for things that may be triggering panniculitis, like tuberculosis.

Panniculitis is not too incredibly common, and not all lumps you find on the skin are panniculitis.

There are many other conditions that can cause painful lumps and bumps underneath the skin’s surface: cysts and boils, deep acne lesions (acne nodules or acne cysts), folliculitis, and more.

So, it’s important you don’t try to self-diagnose. Unidentified lumps and bumps on the skin should always be inspected by a physician. Panniculitis can be a sign of something more serious going on, especially when it develops with other symptoms.

There are many types of panniculitis, but by far the most common form is erythema nodosum. This type of panniculitis affects the lower legs, mostly the shins, although it sometimes can happen on the calves and thighs. Other types of panniculitus are incredibly rare.

Because so many things can cause panniculitis, it can sometimes be difficult to get a specific diagnosis. In fact, you may never know exactly what is causing your panniculitis.

Treatment Options

The treatment for panniculitis varies depending on what is causing the condition. Just like there isn’t one sole cause of panniculitis, there isn’t one specific go-to treatment for the problem. Because panniculitis can be caused by many different conditions, treatment will vary from person to person.

You aren't treating the panniculitis itself; there is no specific treatment for panniculitis. The focus is on treating the underlying cause of panniculitis and easing symptoms to make you more comfortable.

Anti-inflammatory pain killers like ibuprofen can help lessen the swellings and make them feel less tender. Your doctor may prescribe antibiotics as well, if you have a bacterial infection. In severe, long-lasting cases, immunosupressants, corticosteroids, and chemotherapy treatments may be used.

Most panniculitis cases will heal completely even without treatment, although it can last anywhere from a few weeks to a few months before subsiding. Until then, keeping the area elevated when possible can help the inflammation, as can cold compresses. Try compression stockings if panniculits is on the legs.

If panniculitis was caused by trauma it’s highly unlikely to reoccur (unless you reinjure the area again). For inflammation triggered by other causes, though, or in cases where a specific cause isn't identified, panniculitis is often recurring.

A Word From Verywell

To the untrained eye, many skin problems mimic panniculitis. This is why it’s so important to get a proper diagnosis. Also, because panniculitis can be a sign of something more serious, you do want to be seen by a physician.

Panniculitis can come and go, which can be frustrating especially if it has no clear cause or trigger. Work closely with your physician to come up with a plan to control or minimize the flare ups. Most importantly, take it easy on yourself and get plenty of rest to allow your body to heal.

Sources:

Blake T, Manahan M, Rodins K. "Erythema Nodosum - a Review of an Uncommon Panniculitis." Dermatology Online Journal. 2014 Apr 16;20(4):22376.

Chowaniec M, Starba A, Wiland P. "Erythema Nodosum - Review of the Literature." Reumatologia. 2016;54(2):79-82.

"Erythema Nodosum." MedlinePlus Medical Encyclopedia, U.S. National Library of Medicine, National Institutes of Health, 16 Aug. 2017.

Morrison LK, Rapini R, Willison CB, Tyring S. "Infection and Panniculitis." Dermatologic Therapy. 2010 Jul-Aug;23(4):328-40.

Wick MR. "Panniculitis: A Summary." Seminars in Diagnostic Pathology. 2017 May;34(3):261-272.

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