Information on the following diseases can be found in the Related Disorders section of this report:

• Cytophagic Histiocytic Panniculitis
• Sweet Syndrome
• Erythema Nodosum

Idiopathic nodular panniculitis usually begins gradually. Abnormal bumps or masses (nodules) appear in the fatty layer under the skin (subcutaneous fat) of the legs, thighs, and buttocks. In some cases, the arms, abdomen, and/or face may be involved. These nodules are usually 1-2 centimeters wide and may be either painful and tender or painless. In some cases, the affected area may become red (erythema) and waste away (atrophic), eventually healing and leaving a slight depression.

Another common finding associated with idiopathic nodular panniculitis is recurrent episodes of fever. Additional symptoms include a general feeling of ill health (malaise), fatigue, muscle pain (myalgia), joint pain (arthralgia), and/or abdominal pain. In some cases, weight loss may occur and nausea may be present. In rare cases, inflammation of skin the near the eye (orbital inflammation) may result in abnormal protrusion of the eye (proptosis).

In some cases, inflammation of the subcutaneous layer of fat (panniculitis) may affect additional organ systems of the body (systemic), potentially resulting in blood abnormalities such as low levels of circulating red blood cells (anemia), liver involvement such as an abnormally large liver (hepatomegaly), and lung involvement such as accumulation of fluid in the membrane surrounding the lungs (pleural effusion).
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The exact cause of idiopathic nodular panniculitis is unknown. There are numerous different causes that may be associated with the development of panniculitis including gout, diabetes mellitus, systemic lupus erythematosus, subacute bacterial endocarditis, tuberculosis, iodide or bromide therapy, withdrawal from large doses of corticosteroids, or pancreatitis. Sometimes the cause may be identified as an allergy or possibly a predisposition of fatty tissue to a granulomatous reaction.
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Idiopathic nodular panniculitis is a rare disorder that may affect males and females of any age group. According to the medical literature, most cases have been young adult females.

The term Weber-Christian disease has been used to describe a group of syndromes or diseases characterized by nodular panniculitis and additional symptoms involving various organ systems of the body (systemic). However, the association of nodular panniculitis and systemic findings may occur due to a variety of causes or secondary to several different diseases, such as systemic lupus erythematous, alpha-1-antitrypsin disease, and connective tissue disease. The term Weber-Christian disease has led to confusion in the medical literature and many researchers suggest that its use be abandoned.
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Symptoms of the following disease may be similar to those of idiopathic nodular panniculitis. Comparisons may be useful for a differential diagnosis:

Cytophagic histiocytic panniculitis is a rare disorder affecting the skin and the layers of fatty (adipose) tissue directly under the skin (subcutaneous). The first symptom of this disease is typically the appearance of reddened and tender nodules (lesions) under the skin. In addition, a fever may be present. Most affected individuals have a chronic form of the disease. As the disease progresses, the lesions may increase in size and number and the deeper layers of the skin and other organs of the body (e.g., bone marrow, lymphatic system, etc.) may also be affected. In some severe cases, blood clotting (coagulation) abnormalities and liver malfunction may also be present. The exact cause of cytophagic histiocytic panniculitis is not known.

Sweet syndrome is a rare skin disorder characterized by fever, inflammation of the joints (arthritis), and the sudden onset of a rash. The rash consists of bluish-red, tender papules that usually occur on the arms, legs, face or neck, most often on one side of the body (asymmetric). In approximately 80 percent of cases, Sweet syndrome occurs by itself for no known reason (idiopathic). In 10 percent to 20 percent of cases, the disorder is associated with an underlying malignancy, usually a hematologic malignancy such as certain types of leukemia. The exact cause of Sweet syndrome is unknown. (For more information on this disorder, choose “Sweet” as your search term in the Rare Disease Database.)

Erythema nodosum is a group of skin disorders that are characterized by painful, red bumps or lesions (nodules) most often affecting the lower legs (extremities). Erythema nodosum is often associated with recurring episodes of fever, malaise, fatigue, and joint pain. The exact cause of erythema nodosum is unknown.
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Diagnosis
A diagnosis of idiopathic nodular panniculitis is made based upon a detailed patient history, a thorough clinical evaluation, and identification of classic symptoms. In many cases, surgical removal (biopsy) and microscopic examination of small samples of deep skin tissue may reveal inflammation of subcutaneous layers of fat tissue.

Treatment
Treatment of idiopathic nodular panniculitis is symptomatic and supportive. In some cases, skin lesions may heal spontaneously (remission). However, they often return (recur). Affected individuals should receive a thorough clinical examination to determine whether the idiopathic nodular panniculitis is actually occurring secondary to another condition, as treatment of that primary condition may alleviate the symptoms of idiopathic nodular panniculitis.

In severe cases, corticosteroid treatment (e.g., prednisone) may be effective under controlled conditions (e.g., limited duration).
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Treatment of idiopathic nodular panniculitis with oral cyclophosphamide (a cytostatic drug) has shown some promise in preliminary clinical trials. More research is necessary to determine the long-term safety and effectiveness of this treatment for idiopathic nodular panniculitis.

Treatment of idiopathic nodular panniculitis with oral cyclosporin A, an immunosuppressive agent, has shown some promise according to the medical literature. In some cases, treatment with cyclosporin A has led to improvement in symptoms including regression of subcutaneous nodes and overall improvement of health. More research is necessary to determine the long-term safety and effectiveness of this treatment for idiopathic nodular panniculitis.

Researchers are studying the use of an immunosuppressive drug known as mycophenolate mofetil as a potential treatment for individuals with idiopathic nodular panniculitis. Initial reports have suggested that individuals taking this medication have experienced rapid improvement of symptoms. However, more research is necessary to determine the long-term safety and effectiveness of this treatment for individuals with idiopathic nodular panniculitis.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, in the main, contact:
www.centerwatch.com

TEXTBOOKS
Fauci AS, et al, eds. Harrison's Principles of Internal Medicine, 14th Ed. New York, NY: McGraw-Hill, Inc; 1998:2212-13.

Bennett JC, Plum F, eds. Cecil Textbook of Medicine. 20th ed. Philadelphia, PA: W.B. Saunders Co; 1996:1507-08.

Burton JL, et al. Subcutaneous fat. In: Champion RH, et al., eds. Textbook of Dermatology. 5th ed. Cambridge, MA: Blackwell Scientific Publications; 1992:2135-52.

JOURNAL ARTICLES
Kovacs M, et al. Successful treatment of Weber-Christian panniculitis with cyclosporin-A. Orv Hetil. 2004;145:827-31.

Baskan EB, et al. Effective treatment of relapsing idiopathic nodular panniculitis (Pfeifer-Weber-Christian disease) with mycophenolate mofetil. J Dermatolog Treat. 2003;14:57-60.

Hyun SH, et al. Weber-Christian disease presenting with proptosis: a case report. J Korean Med Sci. 2000;15:247-50.

Iwasaki T, et al. Successful treatment of a patient with febrile, lobular panniculitis (Weber-Christian disease) with oral cyclosporin A: implications for pathogenesis and therapy. Intern Med. 1999;38:612-14.

Miyasaki N. Steroid-resistant Weber-Christian disease. Intern Med. 1999;38:522.

White JW Jr, et al. Weber-Christian panniculitis: a review of 30 cases with this diagnosis. J Am Acad Dermatol. 1998;39:56-62.

Asauliuk IK, et al. Pfeifer-Weber-Christian disease with 20-year course. Lik Sprava. 1998;7:154-59.

Enk AH, et al. Treatment of relapsing idiopathic nodular panniculitis (Pfeiffer-Weber-Christian disease) with mycophenolate mofetil. J Am Acad Dermatol. 1998;39:508-09.

Cook JN, et al. Proptosis as the manifesting sign of Weber-Christian disease. Am J Ophthalmol. 1997;124:125-26.

Viravan S, et al. Successful treatment of cytophagic histiocytic panniculitis by cyclosporin A: a case report. Asian Pac J Allergy Immunol. 1997;15:161-66.

Khan GA, et al. Recognizing Weber-Christian disease. Tenn Med. 1996;89:447-49.

White WL, et al. Panniculitis: recent developments and observations. Semin Cutan Med Surg. 1996;15:278-99.

Biasi D, et al. Weber-Christian disease with calcinosis: a case report. Clin Rheumatol. 1996;15:624-25.

Kumagai-Kurata N, et al. Idiopathic lobular panniculitis with specific pleural involvement. Eur Respir J. 1995;8:1613-15.

Akama H, et al. Glucocorticoid-unresponsive fever in a patient with Weber-Christian disease. Br J Clin Pract. 1994;48:161-62.

Ohara S, et al. Myalgia as the major symptom in systemic panniculitis (Weber-Christian disease). Eur Neurol. 1992;32:321-26.