Erdheim-Chester disease
This disease – which is extremely rare, with just 500 cases noted before 2014 – occurs when the body overproduces macrophages. It’s most common in middle-aged people and in men, who make up 75% of cases. About a quarter of patients develop skin lesions: Red-brown to yellow nodules and xanthelasma-like indurated plaques on the eyelids, scalp, neck, trunk, and axillae, and “other cutaneous manifestations have been reported in patients,” Dr. Callen said.
The disease also frequently affects the bones, large vessels, heart, lungs, and central nervous system. Interferon-alpha is the first-line treatment, and there are several other alternative therapies, although 5-year survival (68%) is poor, and it is especially likely to be fatal in those with central nervous system involvement.
Eosinophilic fasciitis
Eosinophilic fasciitis (EF) “is a disorder of unknown etiology that causes sclerosis of the skin” without Raynaud’s phenomenon, Dr. Callen said. Look for erythema, swelling, and induration of the extremities that is accompanied by peripheral eosinophilia, and if necessary, confirm the diagnosis with full skin-to-muscle biopsy or MRI.
There are many possible triggers, including strenuous exercise, initiation with hemodialysis, radiation therapy and burns, and graft-versus-host disease. Other potential causes include exposure to medications such as statins, phenytoin, ramipril, subcutaneous heparin, and immune checkpoint inhibitor therapy. The disorder is also linked to autoimmune and hematologic disorders.
Dr. Callen, who highlighted EF guidelines published in 2018, said treatments include physical therapy, prednisone, methotrexate, mycophenolate, and hydroxychloroquine.
Metastatic Crohn’s disease
This is a rare granulomatous inflammation of skin that often affects the genitals, especially in children. It is noncontiguous with the GI tract, and severity of skin involvement does not always parallel the severity of the disease in the GI tract, Dr. Callen said. However, the condition can occur before or simultaneously with the development of GI disease, or after GI surgery.
He highlighted a review of metastatic Crohn’s disease, published in 2014, and noted that there are multiple treatments, including systemic corticosteroids, tumor necrosis factor–alpha inhibitors, and topical therapies.
Dr. Callen reported no relevant disclosures.