Differentials
Weber-Christian disease
SIGNS / SYMPTOMS
Lobular panniculitis without vasculitis.
Occurs predominantly in women between the ages of 30 and 60 years.
Erythematous, edematous, tender subcutaneous nodules 1-2 cm in size, involving the thighs, lower legs, arms, trunk, and face.
Occasionally, the lesions discharge an oily, yellow-brown liquid.
Inflammation can involve lungs, intestines, pleura, myocardium, pericardium, spleen, kidney, and adrenal glands.
INVESTIGATIONS
High sedimentation rate and leukocytosis may be the only laboratory abnormalities seen.
Biopsy of the lesion shows neutrophils, lymphocytes, macrophages, and foamy histiocytes in the lobules of subcutaneous tissue. Fibroblasts replace the initial inflammatory cellular response.
Alpha-1 antitrypsin-deficiency
SIGNS / SYMPTOMS
Characterized by recurrent, tender, erythematous, subcutaneous ulcerating nodules, 1-5 cm wide.
There is often a family history.
INVESTIGATIONS
Serum alpha-1 antitrypsin level is low.
Nodular vasculitis (erythema induratum or Bazin disease)
SIGNS / SYMPTOMS
More common in women.
Presents as chronic, recurrent, erythematous, tender subcutaneous nodules that frequently ulcerate.
Especially common over the posterior calves.
INVESTIGATIONS
Can be associated with tuberculosis, giving a positive tuberculin test.
A chest x-ray may show evidence of active tuberculosis.
Biopsy reveals tuberculoid granulomas with caseation and a giant cell reaction.
Cutaneous polyarteritis nodosa
SIGNS / SYMPTOMS
Typically presents with painful subcutaneous nodules with associated livedo racemosa and ulceration. Systemic symptoms may include fever, arthralgias, myalgias, and peripheral neuropathy.
INVESTIGATIONS
Biopsy demonstrates segmental necrotizing medium artery vasculitis.
Subcutaneous infections (bacterial, mycobacterial, or fungal)
SIGNS / SYMPTOMS
Often suppurative, ulcerative, purpuric, and/or multifocal. Usually in patients with a history of trauma or systemic symptoms of infection.
INVESTIGATIONS
Skin biopsy suggestive of infection including possible positive organism-specific infectious stains. Tissue culture helpful in elucidating the particular organism.
Nodular fat necrosis
SIGNS / SYMPTOMS
Characterized by hard nodules and ulcerations on the legs in the setting of a history of trauma and/or venous insufficiency. Overlying warmth and erythema are absent.
INVESTIGATIONS
Biopsy of a lesion demonstrates nonviable adipocytes encapsulated by fibrotic tissue, potentially accompanied by lipomembranous changes and calcification.
Erythema nodosum leprosum
SIGNS / SYMPTOMS
Usually arising in patients with lepromatous or borderline leprosy, particularly those undergoing treatment. Often accompanied by systemic symptoms such as fever, arthralgias, arthritis, myalgias, and hepatosplenomegaly.
INVESTIGATIONS
Biopsy of a lesion demonstrates a small vessel vasculitis.
Subcutaneous granuloma annulare
SIGNS / SYMPTOMS
Characterized by painless skin colored nodules, usually in children, and usually accompanied by lesions elsewhere. Often associated with the classic intradermal lesions of granuloma annulare.
INVESTIGATIONS
Biopsy demonstrates degenerated collagen and elastin with mucin deposition, a dermal perivascular and interstitial lymphohistiocytic infiltrate, or palisading granulomas of lymphocytes and histiocytes surrounding mucin.
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