Cutaneous lupus erythematosus

by Bret Kenny and Allison Osmond MD FRCPC
November 14, 2024

Cutaneous lupus erythematosus (CLE) is the term doctors use when a disease called lupus erythematosus affects the skin. About two-thirds of patients with lupus will develop CLE. Many patients with CLE also have other organs, such as the heart, lungs, kidneys, muscles, and joints, affected by lupus.

Lupus erythematosus

Lupus erythematosus is an autoimmune disease resulting in increased inflammation throughout the body. The inflammation, or damage, can be caused directly by immune cells or specialized proteins called antibodies produced by immune cells. In most patients with lupus, the immune system makes anti-nuclear antibodies (ANA), which are given this term because they stick to the nucleus of normal cells.

What causes lupus erythematosus?

Lupus erythematosus is caused by genetic, environmental, and immune system factors, leading to increased inflammation.

• Genetic: Researchers have identified many genes associated with an increased risk of developing lupus erythematosus. Patients with lupus erythematosus often have a family member who is also affected.
• Environmental: Lupus erythematosus can be triggered by environmental factors in individuals genetically predisposed to this disease. One of the most common triggers is sun exposure, as well as cigarette smoking, hormones, infections, and some medications.
• Immune system: Lupus erythematosus is thought to involve multiple parts of the immune system, including antibodies and proteins, which lead to increased inflammation. Specialized immune cells called T-cells and components of our cellular immune system play an important role in developing and maintaining lupus erythematosus.

Types of cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) can present with a broad range of skin lesions. Doctors divide these skin lesions into three categories or types: acute, subacute, and chronic or discoid.

Acute cutaneous lupus erythematosus

Acute CLE often presents as a red rash on the cheeks and nose called a “butterfly rash.” Most patients with acute CLE eventually develop lupus in other parts of the body.

Subacute cutaneous lupus erythematosus

Subacute CLE most often presents as a red, raised, scaly rash on sun-exposed areas of the body. Skin lesions are ring-like and may look similar to psoriasis or eczema. Approximately 10-15% of patients with this form of CLE eventually develop lupus in other parts of the body.

Chronic/discoid cutaneous lupus erythematosus

Chronic or discoid CLE often starts with a red, round, scaly rash on the scalp, face, ears, and other sun-exposed areas. Skin lesions may heal but leave discolored scars and hair loss on the scalp. Approximately 5-10% of patients with this form eventually develop lupus in other parts of the body.

How is this diagnosis made?

The diagnosis of CLE requires information from various sources, including your medical history, a physical examination, blood tests, and a skin biopsy. Your medical team will work collaboratively to gather and share this information to determine the correct diagnosis.

Microscopic features of this disease

A skin biopsy is a procedure in which a small sample of tissue is removed and sent to a pathologist for examination under a microscope. The sample can be used to look for inflammation, tissue damage, and abnormal antibodies in the skin.

Common microscopic features of cutaneous lupus erythematosus include:

• Vacuolar interface change: This term describes damage at the bottom of the epidermis where the squamous cells meet the dermis.
• Civatte or colloid bodies: A civatte or colloid body is a damaged squamous cell. As a squamous cell dies, it becomes small and turns bright pink.
• Thickening of the basement membrane: The basement membrane is the thin layer of tissue that separates the epidermis from the dermis. In CLE, it becomes abnormally thick.
• Increased dermal mucin: The dermis is a thick layer of connective tissue below the basement membrane. CLE results in damage to the dermis by inflammatory cells and increased production of a substance called mucin.

Direct immunofluorescence

Direct immunofluorescence (DIF) is a test that pathologists perform to look for specific proteins in a tissue sample. Unlike most tissue samples, which are examined using normal light, DIF tissue samples are examined using fluorescent light. This makes it easier for your pathologist to see abnormal proteins in the sample. In patients with CLE, tissue samples analyzed by DIF will often show increased amounts of immune system-related proteins in the area of the basement membrane. These proteins include IgG, IgM, IgA, and C3.