Discoid Lupus 1_0114 Derm Dx
Discoid Lupus 2_0114 Derm Dx
Discoid Lupus 3_0114 Derm Dx
A 45-year-old black patient presents complaining of hair loss that has been progressive over several years. Topical corticosteroids have not helped her. She takes hydrochlorothiazide for hypertension.
Recent complete blood count (CBC) and complete metabolic panel were normal. The patient’s antinuclear antibody (ANA) test is negative.
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Discoid lupus erythematosus (DLE) is a subset of chronic cutaneous lupus erythematosus. It is predominantly a purely cutaneous disease process, with low incidence of progression to systemic lupus erythematosus (SLE). There is a predilection for females with onset from age 20 to 45 years; peak incidence occurs in the fourth decade of life.
Discoid lesions often start as bright red papules, which evolve into elevated, violaceous 1 cm to 2 cm flat-topped plaques. Lesions are often asymptomatic, but may be pruritic.
They may be round or oval, annular or polycyclic and display sharply defined, irregular borders, giving the lesions a disk-like appearance. The plaques have adherent scales that penetrate the hair follicles.
Microscopic examination of the peeled plaques will show a characteristic ‘carpet track scale.’ Lesions often expand peripherally and display early central regression due to epidermal atrophy. The result is a smooth, wrinkled and hypopigmented central area, which may be particularly disfiguring in blacks. Lesions may last for months to years.
The natural course is either complete regression (50% in localized and <10% in generalized) or further progression. Progressive lesions result in depressed, dyspigmented areas of scarring, alopecia and atrophy. The scarring process may be destructive in severe cases. Although uncommon, squamous cell carcinoma may develop into long-standing lesions.
Discoid lesions are most commonly distributed on the face, scalp and ears (80%), but may appear anywhere on the body. The localized subtype has lesions limited to the head and neck, whereas the generalized subtype has lesions both above and below the neck.
Very rarely will there be lesions below the neck without lesions also above the neck.
Generalized type lesions are often asymmetric and may involve the forearms, hands, fingers, toes and trunk. Lesions on the palms and soles may be keratotic or ulcerative. Some patients will present with lesions in a photo-distribution, whereas many will have lesions in sun-protected areas. The relationship between sun exposure and lesion development is unclear.
Less than 5% of patients may have mucosal involvement, including the lips, buccal, nasal, conjunctivae and genital mucosa. Mucosal involvement may be erythematous, dyspigmented or ulcerative. Additionally, some patients may have nail dystrophy.
A rare variant, hypertrophic discoid lupus erythematosus, presents with thick, scaling discoid lesions. The hyperkeratosis may cover the entirety of the discoid lesion, or involve only the periphery. These hypertrophic lesions are most prominent on the extensor forearms. Typical, non-hypertrophic discoid lesions are often concurrently present as well.
In a patient with discoid lesions, the diagnosis of discoid lupus erythematosus is established with biopsy. Histologic examination of the involved skin will show epidermal atrophy, follicular plugging, hyperkeratosis and hydropic degeneration of the epidermal basal cell inflammatory infiltrate. The sub-epidermal basement membrane is thickened, which is best demonstrated with strong Periodic acid-Schiff (PAS) staining. Very few patients with discoid lupus erythematosus (<5%) will have an ANA titer greater than 1:160.
Patients with widespread, active disease may have antibodies to single stranded DNA (anti-ssDNA); otherwise other antibodies associated with lupus (anti-dsDNA, anti-Sm) are usually negative, unless the patient has concomitant system lupus erythematosus.
Although discoid lupus erythematosus is usually a purely cutaneous disease process, it is important to remember that the discoid lesions may be a presenting symptom for SLE. The American Rheumatism Association (ARA) has outlined SLE 11 criteria, four of which must be present for classification. The discoid rash counts as one criterion.
The percentage of individuals with DLE that progress to SLE is unclear, but has been reported as anywhere from 0% to 28%. This progression may occur within months of the onset of discoid lesions or may happen after 20 years or more. However, 70% of those who develop SLE will do so within 5 years.
Risk factors for the development of SLE include the generalized subtype, arthralgias, arthritis, nail dystrophy, hematological abnormalities (anemia, leukopenia), an elevated erythrocyte sedimentation rate (ESR), and positive antinuclear antibodies (ANA).
The clinician, therefore, must have a healthy suspicion for the development of SLE in a patient who presents with discoid lesions. Recommendations to monitor for systemic spread include periodic complete skin examination, joint assessment, CBC, urinalysis, and assays for ANA and ESR.
Early diagnosis and treatment of DLE is imperative to prevent scarring. Topical or intralesional glucocorticoids and antimalarials are mainstays of treatment. Intralesional triamcinolone acetonide at a concentration of 3 to 5 mg/ml is often effective for smaller lesions. Injections may be given monthly.
Hydroxychloroquine is the most commonly used systemic agent, given at a dose < 6.5 mg/kg/day to avoid ocular toxicity. Quinacrine may be added if hydroxychloroquine alone is ineffective.
Response to antimalarials is slow, often requiring two to three months of treatment before results are observed. Therefore, intralesional glucocorticoids are often used initially with antimalarials.
Alternative treatments include retinoids (acitretin 0.5 mg/kg) and thalidomide (100-300 mg/day). It is imperative that patients protect themselves from the sun, as solar exposure may initiate or exacerbate lesions.
Other answer choices:
Lichen planopilaris is follicular lichen planus of the scalp, which presents with erythema and scaling around hair follicles. Patchy areas of alopecia often develop as the lesions spread outward, leaving a central area of scarring.
The peripheral border of lichen planopilaris is more active than that of discoid lupus. These lesions may be painful and may involve the skin or mucosa Ultimately, diagnosis is established with biopsy.
Subacute cutaneous lupus erythematosus presents most commonly in young and middle aged white females. It is uncommon in blacks and Hispanics. Cutaneous manifestations are of two varieties – psoriasiform papulosquamous (sharply defined, erythematous plaques with scale) and annular (red annular lesions with central regression).
Lesions often involve the trunk, upper back, shoulders, extensor surface of the arms and dorsal hands. Rarely, lesions are found below the waist. Lesions tend to resolve over time, leaving hypopigementation and telangiectasia. However, there is no scarring as in discoid lupus.
Additionally, follicular plugging and hyperkeratosis are not seen in subacute cutaneous erythematosus. The lesions of subacute cutaenous lupus erythematosus are often recurrent and may be related to sun exposure. Many patients may have concomitant arthritis and arthralgias, and the majority will have SS-A antibodies.
Drug-induced systemic lupus erythematosus may present as a mild form of systemic lupus, usually in older patients. Typical presentation consists of arthritis, arthralgias and myalgias. However, some patients may present with serositis and hepatosplenomegaly.
Many drugs have been implicated including procainamide, hydralazine, isoniazid, methydopa and chlorpromazine. Patients typically have positive ANA and positive anti-histone antibodies.
Christopher B. Rizk, BA, and Andrew S. Fischer, BA, are medical students at Baylor College of Medicine.
Adam Rees, MD, is a graduate of the University of California Los Angeles School of Medicine and a resident in the Department of Dermatology at Baylor College of Medicine also in Houston.
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- Habif TP. “Chapter 17: Connective Tissue Diseases.” Clinical Dermatology: A Color Guide to Diagnosis and Therapy. Philadelphia: Mosby/Elsevier, 2010. pp. 71-692.
- Wolff K, Johnson RA, Suurmond D, Fitzpatrick TB. “Section 332: The Skin in Immune, Autoimmune, and Rheumatic Disorders.” Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology. New York: McGraw-Hill, 2013. pp. 32-342.
- Chong BF, Song J, Olsen NJ. “Determining risk factors for developing systemic lupus erythematosus in patients with discoid lupus erythematosus.” Br J Derm. 2012:166: 29-35.