Answer to Dermacase

2. Cutaneous lupus erythematosus (subacute)

Subacute cutaneous lupus erythematosus (SCLE) is characterized by erythematous, photosensitive, non-scarring lesions and systemic signs and symptoms, such as musculoskeletal complaints (arthralgia and arthritis), serologic abnormalities (anemia and thrombocytopenia), pleurisy, pericarditis, renal disease, and neurologic disease.1 About half of SCLE patients have 4 or more of the American College of Rheumatology’s criteria for systemic lupus erythematosus2; however, SCLE patients’ systemic disease tends to be much milder.1,3 Subacute cutaneous lupus erythematosus is primarily a disease of white women; mean age of onset is between the third and fifth decades.1,4 The prevalence of SCLE is estimated at 1 to 5 cases per 100 000 population.3

The primary lesions among patients with SCLE are erythematous papules or plaques covered with fine scale. Lesions can expand and coalesce into large plaques that mimic psoriasis (papulosquamous subtype, Figure 1) or can expand and clear centrally, producing large annular polycyclic lesions (annular-polycyclic subtype). The papulosquamous form is the most common, and most SCLE patients exhibit only 1 morphologic subtype of the disease.

Characteristic SCLE distribution is in sun-exposed areas: neck, face, extensor arms, dorsal hands, lower limbs, and scalp.5 The disease is often aggravated by trauma and light. Resolving SCLE lesions characteristically do not produce scarring or dermal atrophy but they might result in telangiectases and pigmentary changes.1 Other types of cutaneous lupus erythematosus lesions can be found in SCLE patients and include malar eruptions (Figure 2), periungual telangiectases, and livedo reticularis (Figure 3).5

Diagnosis

Diagnosis of SCLE is based on history, physical examination, and laboratory investigations. Many medications have been implicated in onset and exacerbation of disease; hydrochlorothiazide and terbinafine are the most common.1 Every newly diagnosed SCLE patient should be screened for underlying systemic lupus erythematosus.

Patients should be asked about photosensitivity, rashes, mucosal ulcerations, fatigue, arthralgia and arthritis, alopecia, and symptoms of associated systemic disease. A complete physical examination guided by history is advised.3 Several laboratory investigations can be of value in diagnosis of SCLE. An antinuclear antibody test is commonly positive in patients with SCLE, but is not diagnostic of the disease. Most SCLE patients have anti-Ro(SSA) autoantibodies, which are recognized as a characteristic marker of the disease. There is a strong association between SCLE and anti-Ro(SSA) autoantibodies, especially in patients negative for anti–double-stranded DNA.4 In addition, a complete blood count and differential count, serum chemistry profile, erythrocyte sedimentation rate assessment, and urinalysis are recommended to screen for systemic disease. Skin biopsy confirms the diagnosis. Referral to a dermatologist or rheumatologist is highly recommended to confirm an SCLE diagnosis and rule out systemic disease.4

Treatment

The goals of SCLE treatment are to halt disease progression and improve patients’ appearance. Patients should be educated about continuous use of sun-screen with a sun protection factor of at least 30, wearing clothing that provides protection from the sun, and avoiding heat and sun. Cosmetics can be used to camouflage dyspigmentation and telangiectases. Depending on the location of the affected area and the age of the patient, mid- to high-potency topical steroids can be used for localized disease. If they do not work, physicians with experience can try using intralesional triamcinolone acetonide.3 Occasionally, topical calcineurin inhibitors, such as topical tacrolimus, are used on the head and neck, axillae, or groin. If topical corticosteroid preparations are ineffective or a large body-surface area is involved, 20 to 40 mg of prednisone daily for 3 to 4 weeks, in tapering doses, can be administered to control the disease.1

Antimalarial agents, such as 200 to 400 mg of hydroxychloroquine daily, are first-line agents for systemic therapy.3 Other systemic therapies include methotrexate, azathioprine, retinoids, and dapsone. These drugs have been shown to be effective in some cases and in anecdotal reports for those resistant to antimalarials.1