Diagnosis: Discoid lupus erythematosus
Lupus is a common autoimmune disease that often has cutaneous features. Patients range from healthy people with purely cutaneous disease to those with severe multisystem disease in which the skin is merely one of the organs involved.
Besides the classic butterfly rash of systemic lupus erythematosus (SLE), it is important to recognize all major classes of cutaneous lupus. Each has a unique course and complications, and each confers its own risk of underlying disease.
Our patient had discoid lupus erythematosus (DLE), a chronic scarring photosensitive dermatosis with a classic and recognizable morphology. Discoid lesions make up more than 50% of all cutaneous forms of lupus. DLE is most often found in young adults and affects women twice as often as men. Most lesions are asymptomatic, but some may demonstrate mild itching or burning. The initial erythematous plaques have little scale. As they expand, the lesions thicken and become hyperpigmented in more active areas. Older lesions often “burn out” with white atrophic scars.
Most plaques develop a characteristic dilation of follicles with subsequent keratin plugging. Reflecting the photosensitivity of DLE, lesions are often found on the head and neck; involvement of the ears is characteristic.
Patients with DLE lesions almost always have disease confined to the skin. In a small number of patients, lesions disseminate to all areas of the body; these patients are much more likely to meet criteria for SLE. While approximately one in five DLE patients will be positive for antinuclear antibody, only about 5% will ever meet criteria for SLE.1 Routine follow-up and clinical monitoring is still important, since no single reliable finding rules out underlying disease. When disease is not confined to the head and neck, the chance of systemic disease is greater, and workup should be more aggressive.
Another common form of cutaneous lupus is subacute cutaneous lupus erythematosus (SCLE). SCLE begins as photodistributed red papules that quickly become annular red rings with overlying psoriasiform scale in areas exposed to sun. As the lesions grow together, they form characteristic polycyclic scaling plaques. SCLE lesions are most often seen in light-skinned patients and affect females more often than males. Scarring is rare. Unlike patients with DLE, patients with SCLE are likely to have an underlying connective tissue disease.
When cutaneous lupus is suspected, begin by defining the scope of disease. Clinical morphology may be sufficient to diagnose cutaneous lesions. Punch biopsy is helpful if there is doubt. Specimens should be taken from fresh lesions and assessed with routine hematoxylin and eosin stains as well as immunofluorescence, although immune complexes are not always found in purely cutaneous lupus. Biopsy will confirm a collagen vascular disease, but distinguishing type is difficult. Lab tests should be directed by history and physical to look for systemic involvement. Review the patient’s medications.
Treatment of any cutaneous lupus begins with strict photoprotection. Sun avoidance along with a strong UVA/UVB sunblock is a must. For limited disease, potent topical steroids are a reasonable next step to decrease symptoms and resolve lesions. In DLE, which tends to have thicker lesions, intralesional triamcinolone is also very useful. The cosmetic appearance of discoid lesions should not be neglected and coverups, such as Covermark or Dermablend, should be discussed.
In more extensive skin disease, lesions refractory to topical/ intralesional steroids, or suspected systemic involvement, antimalarials are the most common medication used. Retinoids, thalidomide, and immunosuppressants are second-line agents.
Our patient had no symptoms to suggest systemic involvement. She was treated initially with intralesional steroids and sun protection. Hydroxychloroquine was added at 200 mg twice daily, as she continued to have a few new lesions. Our next step, if she does not respond, will be thalidomide after significant discussion of the need for adequate contraception.
Dr. Sonabend has a private dermatology practice in Houston. Dr. Hsu is professor of dermatology at Baylor College of Medicine in Houston.
1. Callen JP, Jorizzo JL, Piette WW, et al. Dermatological Signs of Internal Disease. 3rd ed. Philadelphia, Pa.: WB Saunders; 2003:1-11.