Understanding Panniculitis: Inflammation of Subcutaneous Fat
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Panniculitis is inflammation in the layer of fat beneath your skin, most often causing tender lumps (nodules) on the lower legs. It is a group of conditions with many possible triggers, including infections, injury, certain medicines, and autoimmune or inflammatory diseases. Diagnosis often relies on examining a tissue sample under a microscope, and treatment targets the underlying cause. On average, symptoms usually clear about six weeks after treatment starts, although the condition can be chronic and come back [1] [2].
Quick Answer: What is panniculitis?
Panniculitis is inflammation in the layer of fat under the skin, causing nodules most commonly on the lower legs. Triggers include infections, injury, certain medicines, Crohn's disease and sarcoidosis. Diagnosis often relies on a tissue sample. Treatment depends on the cause, and symptoms usually clear about six weeks after treatment starts, though it can be chronic. [1] [2]
What the research says
Diagnosis needs both the microscope and the clinic. A narrative review of common noninfectious panniculitis in adults concluded that histopathology remains a key component of diagnosis, but clinical characteristics (patient history, distribution, and morphology) provide substantial aid (Maniam et al., Arch Dermatol Res, 2025).
It can be mistaken for infection. A dermatology review of conditions that mimic infection lists panniculitis among them, noting that lesions not accurately recognized may be treated with antimicrobial agents, adding cost, potential risk, and inconvenience (Ricketts et al., Int J Dermatol, 2011).
Mesenteric panniculitis is a gut condition with its own guidance. The American Gastroenterological Association issued a Clinical Practice Update on sclerosing mesenteritis, a condition indexed with mesenteric panniculitis, reviewing the evidence on diagnosis and treatment (Worthington et al., Clin Gastroenterol Hepatol, 2025).
Research summaries are based on article abstracts retrieved from PubMed.
What Is Panniculitis?
Panniculitis means inflammation in the layer of fat just beneath your skin [1]. The word covers a group of conditions rather than a single disease, and these conditions can be challenging to tell apart by appearance alone [2]. That is why identifying the specific type matters.
Nodules are most common on the lower legs [1]. Because several skin conditions can resemble an infection, panniculitis can be mistaken for one and treated with antimicrobials that are not needed [3].
What are the types of panniculitis?
Type | What it is |
|---|---|
Cold panniculitis | Linked to cold exposure. Infants and young children often receive this diagnosis. |
Erythema nodosum | A common type that typically causes tender lumps on the shins. |
Infectious panniculitis | Inflammation of the fat layer caused by an infection. |
Lupus panniculitis | Occurs in people with lupus, an autoimmune disease. |
Mesenteric panniculitis | Affects the fat in the mesentery, the tissue that holds the intestines in place, rather than the skin. |
Source: type names from Cleveland Clinic [1].
Visual overview of panniculitis types and their typical locations on the body.
What are the symptoms of panniculitis?
The main sign is one or more tender nodules under the skin, most often on the lower legs [1]. Some people also have symptoms that affect the whole body [1]:
Fever
Fatigue
Joint and muscle pain
Nausea and vomiting
After a nodule heals, you may notice a dimple or dent in the skin [1].
What causes panniculitis to develop?
Panniculitis is a reaction to a trigger, such as infections, injury, certain medicines, autoimmune or inflammatory conditions, or cold exposure, and the triggers vary. Cleveland Clinic lists the following [1]:
Infections, such as tuberculosis and pneumonia
Injury to the area
Medicines, including contraceptive pills and penicillin
Autoimmune and inflammatory conditions, including Crohn's disease, sarcoidosis, and inflammatory bowel disease
Cold exposure, in the case of cold panniculitis
How is panniculitis diagnosed?
Because panniculitis can look like other conditions, diagnosis combines your medical history, where the nodules are, and how they look. Histopathology, a microscope exam of a tissue sample (usually from a skin biopsy), is often a key step [2].
Infographic outlining the diagnostic process, including physical examination and skin biopsy.
How is panniculitis treated?
Treatment depends on the cause and how severe your symptoms are. The goal is to address the trigger while easing pain and swelling [1].
Medical treatment
Cleveland Clinic lists these options [1]:
Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation
Corticosteroids and other immunosuppressants to calm the immune response
Antibiotics or antivirals when an infection is the cause
Dapsone or thalidomide
Chemotherapy drugs, for severe symptoms
Self-care
Wear compression garments
Elevate your legs
Follow a Mediterranean-style diet
Self-care measures are from Cleveland Clinic [1].
Overview of treatment options, from prescribed medicines to supportive home care.
What is the outlook and recovery for panniculitis?
On average, symptoms usually clear about six weeks after you start treatment. Panniculitis can also be chronic, with symptoms that come and go [1]. It doesn't usually cause scarring [1].
When should you see a doctor about panniculitis?
See a healthcare provider if you notice tender lumps under the skin, especially if they come with fever, fatigue, or joint or muscle pain [1]. Getting the right diagnosis early helps ensure the cause is treated.
What is the bottom line on panniculitis?
Panniculitis is inflammation of the fat layer under the skin, with several types and many triggers. Diagnosis combines clinical findings with a tissue exam, and treatment targets the cause while easing symptoms. Most people improve within weeks of starting treatment, but because the condition can be chronic, ongoing follow-up with your provider is worthwhile [1] [2].
Frequently Asked Questions
What is panniculitis in simple terms?
Panniculitis is a group of conditions that cause inflammation in the layer of fat under the skin. It most often causes tender lumps on the lower legs.
What are the types of panniculitis?
Named types include cold panniculitis, erythema nodosum, infectious panniculitis, lupus panniculitis, and mesenteric panniculitis.
What causes panniculitis?
Triggers include infections such as tuberculosis and pneumonia, injury, certain medicines such as contraceptive pills and penicillin, and conditions such as Crohn's disease, sarcoidosis, and inflammatory bowel disease.
What are the symptoms of panniculitis?
The main sign is tender nodules under the skin, most often on the lower legs. Some people also have fever, fatigue, joint and muscle pain, nausea, and vomiting.
How is panniculitis diagnosed?
Diagnosis combines your history, the location and look of the nodules, and often histopathology, a microscope exam of a tissue sample such as a skin biopsy.
How is panniculitis treated?
Treatment targets the cause. Options include NSAIDs, corticosteroids, antibiotics or antivirals for infection, dapsone, and thalidomide. Chemotherapy drugs are used for severe symptoms. Compression garments and leg elevation can help.
How long does panniculitis last?
On average, symptoms usually clear about six weeks after treatment starts. The condition can also be chronic, with symptoms that come and go.
Does panniculitis cause scarring?
Panniculitis doesn't usually cause scarring, but you may notice a dimple or dent in the skin after a nodule heals.
Can diet help with panniculitis?
Cleveland Clinic lists a Mediterranean-style diet among self-care measures, alongside compression garments and leg elevation.
When should I see a doctor about panniculitis?
See a healthcare provider if you notice tender lumps under the skin, especially with fever, fatigue, or joint or muscle pain.
Related Resources
External resource for deeper reading:
Cleveland Clinic. Panniculitis. Cleveland Clinic. Medically reviewed; last updated January 8, 2025. https://my.clevelandclinic.org/health/diseases/panniculitis
References
Cleveland Clinic. Panniculitis. Cleveland Clinic Health Library. Last updated January 8, 2025. https://my.clevelandclinic.org/health/diseases/panniculitis
Maniam GB, Limmer EE, Gibson LE, et al. Panniculitis: a narrative review. Arch Dermatol Res. 2025;317(1):373. PMID: 39921712. DOI: 10.1007/s00403-025-03816-9
Ricketts JR, Rothe MJ, Grant-Kels JM. Cutaneous simulants of infectious disease. Int J Dermatol. 2011;50(9):1043-1057. PMID: 22126864. DOI: 10.1111/j.1365-4632.2011.04887.x
Worthington MT, Wolf JL, Crockett SD, et al. AGA Clinical Practice Update on Sclerosing Mesenteritis: Commentary. Clin Gastroenterol Hepatol. 2025;23(6):902-907.e1. PMID: 40119869. DOI: 10.1016/j.cgh.2024.12.025
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have about a medical condition.
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