What is REM syndrome? It sounds like it could be a rock band, a sleep disorder, or science fiction, but it’s actually a rare skin disease. I will present a brief case history.
A middle-aged women was referred by her Dermatologist for a rash of 3 years’ duration. A skin biopsy showed an “atypical lymphoid infiltrate.” This pathologic jargon usually indicates that the lymph cells in the skin are malignant. Her doctor also performed a biopsy to analyze the genes of the lymph cells in the skin, and this test, called “gene rearrangement,” indicated that the cells were reactive or benign.
At this point, she complained of a burning pain in her skin lesions which affected her chest, back, and flank. The rash itself consisted of red papules and plaques in a mottled pattern, except for the oldest lesions on the low back which were thick and bumpy and reddish-purple in color.
I performed deep biopsies in three different areas to confirm the diagnosis. The possibilities included lupus of the skin, “benign lymphocytic infiltrate of Jessner,” lymphoma of the skin, granuloma annulare, and reticular erythematous mucinosis (REM) syndrome.
All three biopsies showed abundant deposits of mucin between collagen bundles which is diagnostic for REM. Most cases occur in women on the chest and back. It is suspected to be caused or aggravated by ultraviolet light or sun exposure, although this patient denied exposing the affected areas to sunlight.
REM is a benign disease of skin only. There is no internal involvement, and blood tests give normal results. The treatment of choice, used in this case, is a form of antimalarial drug called hydroxychloroquine (Plaquenil). Her rash cleared completely after taking Plaquenil 200 mg once daily for 2.5 months. She was also advised to protect her skin from the sun with clothing and broad spectrum sunscreen application.
German scientists have been able to reproduce REM skin lesions in affected patients by exposing skin to high doses of ultraviolet light of various wavelengths. Paradoxically, improvement of the rash of REM has been reported after exposure to UVA1 (wavelength 340-400 nm). However, the risk of flaring the condition exists, and very few UVA1 therapeutic devices are available. This modality should be reserved for patients who either cannot tolerate or fail to respond to Plaquenil. Spontaneous clearing of the rash has been reported as long as 15 years after the onset.