Ichthyosiform Sarcoidosis and Systemic Involvement

Comment

Etiology
Although there are several theories regarding the etiology of sarcoidosis, the exact cause remains unknown. The body’s immune response, infectious agents, genetics, and the environment have all been thought to play a role. It has been well established that helper T cell (T_H1) production of interferon and increased levels of tumor necrosis factor propagate the inflammatory response seen in sarcoidosis.³ More recently, T_H17 cells have been found in cutaneous lesions, bronchoalveolar lavage samples, and the blood of patients with sarcoidosis, especially in those with active disease progression.³ Infectious agents such as mycobacteria and propionibacteria DNA or RNA also have been found in sarcoid samples.⁴ Several HLA-DRB1 variants have been associated with an increased incidence of sarcoidosis.⁵

Presentation
Characteristic dermatologic findings of sarcoidosis include macules, papules, nodules, and plaques located on the face, especially the nose, cheeks, and ears, and on the shins or ankles, as well as similar lesions around tattoos or scars. Sarcoid lesions also have been described as angiolupoid, lichenoid, annular, verrucous, ulcerative, and psoriasiform. Here we present an example of the uncommon type, ichthyosiform. Ichthyosiform sarcoidosis is a rare variant described primarily in dark-skinned individuals, a finding supported by both our case and prior reports. Most reported cases have described IS lesions as having a pasted-on appearance, with adherent centers on the extensor surfaces of the lower extremities, head, and/or neck.⁶ Our case follows this descriptive pattern previously reported with adherent patches limited to the lower extremities.

Histopathology
The key histopathologic finding is the presence of noncaseating granulomas on biopsy. Sarcoid “specific” lesions rest on the identification of the noncaseating granulomas, while “nonspecific” lesions such as erythema nodosum fail to demonstrate this finding.¹

Systemic Involvement
The IS type is believed to be an excellent marker for systemic disease, with approximately 95% of reported cases having some form of systemic illness.⁶ Acquired ichthyosis should warrant further investigation for systemic disease. Early recognition could be beneficial for the patient because the ichthyosiform type is believed to precede the diagnosis of systemic disease in most cases by a median of 3 months.⁶

The most common site of internal sarcoid involvement is the lungs, but the lymph nodes, eyes, liver, spleen, heart, and central nervous system also can be involved. Patients can present with nonspecific symptoms such as erythema nodosum in the skin, dyspnea, cough, chest pain, vision changes, enlarged lymph nodes, headaches, joint pain, fever, fatigue, weight loss, and malaise. According to a PubMed search of articles indexed for MEDLINE using the term ichthyosiform sarcoidosis, 16 cases have been reported in the English-language literature (eTable).^1,6-14 Of these 16 cases, 3 involved men and 13 involved women. The median age of a patient diagnosed with IS was 37 years. The respiratory system was found to be the most common organ system involved (14 of 16 patients), with hilar adenopathy and restrictive lung disease being the most common findings. Neurologic findings and hepatic involvement also were seen in 3 and 3 patients, respectively. Eight of 16 cases had an elevated serum angiotensin-converting enzyme level. Details of systemic involvement in other cases of IS are listed in the eTable.

Management
Most patients are given topical corticosteroids for their cutaneous lesions, but patients with systemic involvement will likely need some type of systemic immunosuppressive therapy to control their disease. Systemic therapy often is warranted in IS because of reports of rapid progression. Our case differs from these prior reports in the relative stability of the disease at the last patient encounter. Systemic treatment commonly includes oral corticosteroids such as prednisone. Other options, such as hydroxychloroquine, methotrexate, azathioprine, pentoxifylline, thalidomide, cyclophosphamide, cyclosporine, and infliximab, can be considered if other treatments fail.¹³ Ichthyosiform sarcoidosis patients should continue to have regular follow-up to monitor for disease progression.

Differential
When evaluating an acquired ichthyosis, dermatologists can consider other associations such as Hodgkin disease, hypothyroidism, multiple myeloma, carcinomatosis, and chronic malnutrition.¹ Skin biopsy demonstrating granuloma formation also is not specific for sarcoidosis. Other etiologies, such as autoimmune diseases, immunodeficiency disorders, infections, foreign body granulomas, neoplasms, and drug reactions, should be considered.¹⁵ All patients with acquired ichthyosis should undergo a thorough evaluation for internal involvement.

Conclusion

We presented a case of IS, a rare type of sarcoidosis commonly associated with further internal involvement of the respiratory, nervous, or hepatic organ systems. Recognition of an acquired form of ichthyosis and its potential disease associations, including sarcoidosis, is important to improve early detection of any internal disease, allowing prompt initiation of treatment.