An uncommon presentation of discoid lupus suggesting systemic evolution

Abstract

Discoid lupus erythematosus (DLE) is a chronic autoimmune condition primarily affecting the head and neck, with palmoplantar involvement (ppDLE) being an uncommon presentation. We present a case of a 46-year-old male with ppDLE and rare perineal involvement, confirmed through biopsy and serological findings, including positive RNP and Sm antibodies. This case underscores the importance of recognizing atypical presentations of DLE, which may indicate a higher risk of systemic progression and require tailored management strategies.

Discoid lupus erythematosus (DLE) is a known chronic autoimmune condition characterized by cutaneous lesions primarily affecting the face, neck, and scalp. Although rare, DLE can involve the palms, soles, or genital areas, as this case presents. Palmar discoid lesions occur in only 2% of patients, and such involvement is associated with higher risk of progression to systemic lupus erythematosus (SLE).^1,2

This case presents a 46-year-old Black male smoker who presented to the rheumatology and dermatology clinic in September 2024 with migratory arthralgia, fatigue, and painful cutaneous lesions. The lesions had been present for over a year, accompanied by a 20lb weight loss. He denied a history of gastrointestinal symptoms, Raynaud’s phenomenon, oral ulcerations, or other features suggestive of connective tissue disease. Lesions were distributed on the palms, scalp, face, ears, groin, arms, perianal region, and soles. He had previously sought primary care in the spring, receiving oral corticosteroids and tacrolimus cream with temporary improvement, with however recurring symptoms after treatment cessation. On examination, the patient exhibited erythematous plaques characterized by depigmentation, scaling on the hands and face, and erosive lesions in the perineal and inguinal regions, with evidence of scarring (see Figures 1 and 2). Differential diagnoses included DLE, sarcoidosis, MDA-5 dermatomyositis, mixed connective tissue disease, contact dermatitis, and vasculitis.

Figure 1.

Facial lesions.

Figure 2.

Palmar lesions.

A skin biopsy revealed lichenoid interface dermatitis, epidermal atrophy, basement membrane thickening, lymphocytic infiltrate, and stromal mucin—findings all consistent with DLE. Extensive and comprehensive laboratory testing was performed, which included serology for autoimmune markers, myositis panel, hepatitis B and C, HIV, skin culture, and coagulation studies. Results showed positive RNP and Sm antibodies, along with lupus anticoagulant, with negative anti-double-stranded DNA and anti-Sjögren’s antibodies, as well as normal levels of C3 and C4, further supporting the diagnosis. Imaging, including a chest X-ray and thoracic CT, showed no interstitial lung disease.

Given these laboratory and biopsy findings, the patient was started on hydroxychloroquine therapy, aspirin (ASA) and a highly potent topical corticosteroid. The patient was educated on photoprotection and smoking cessation. Upon a two-month follow-up, the lesions showed significant improvement, with persistent depigmentation. Pain associated with the lesions resolved, as did the arthralgia.

The pathogenesis of DLE is hypothesized to be multifactorial. Inflammatory cascade, with genetic predisposition and environmental triggers such as ultraviolet (UV) radiation, cigarette smoke, and certain medications are thought to contribute to its development. ³ Risk factors include ethnicity, particularly in African Americans, and female sex. This condition primarily affects photosensitive areas of the skin and may result in various complications. ⁴ When lesions extend beyond the head and neck, as seen in our case, they are predictive of systemic involvement. ³ The largest retrospective study of palmoplantar discoid lupus erythematosus (ppDLE) was conducted in 2023 by the Brigham and Women’s Hospital and Massachusetts General Hospital. Among 751 cases of DLE reviewed, only 43 patients exhibited palmoplantar involvement, highlighting its uncommon presentation. Remarkably, 74.4% of these patients progressed to SLE, significantly higher than the overall estimated progression rate from DLE to SLE, which ranges from 5% to 10%. ² Cases of ppDLE remains particularly underreported, with only seven documented case reports involving this distribution to date.

Additionally, lesions on the palms and soles tend to be more refractory to treatment, posing further management challenges. Traditional treatments for DLE include antimalarials, steroid-sparing immunosuppressants, retinoids, and immunomodulatory agents like thalidomide and lenalidomide ⁵ . However, these therapies have demonstrated inconsistent efficacy in refractory cases.^2,5 Moreover, lesions in the perineal region, as observed in this patient, are rare. While rectal bleeding has been reported in SLE,^6,7 perianal involvement in DLE has not been documented, making this case particularly notable given its already distinctive presentation.

This case underscores the importance of recognizing uncommon presentations of DLE and the need for thorough systemic evaluation to ensure accurate diagnosis and management. Multidisciplinary collaboration among dermatologists, rheumatologists, and other specialists is vital to optimize patient outcomes. Further research is warranted to enhance therapeutic strategies for refractory and atypical manifestations of DLE.