What is Subacute Cutaneous Lupus Erythematosus (SCLE)?

Subacute Cutaneous Lupus Erythematosus (SCLE)

Subacute cutaneous lupus erythematosus (SCLE) is a distinct subset of cutaneous lupus erythematosus characterized by widespread, photosensitive, non-scarring skin lesions with annular and/or psoriasiform patterns, typically associated with anti-Ro/SSA antibodies and mild to moderate systemic involvement. 1

Clinical Features

• SCLE represents an intermediate form between purely cutaneous discoid lupus erythematosus and systemic lupus erythematosus (SLE) 2
• Predominantly affects middle-aged Caucasian women 3
• Characterized by two main types of skin lesions:
  • Annular (ring-shaped) lesions (42% of cases) 4
  • Psoriasiform (scaly, red) lesions (39% of cases) 4
  • Both types may coexist in some patients (16% of cases) 4
• Lesions primarily affect sun-exposed areas, especially the neck and face 4
• Lesions typically do not cause scarring or skin induration 1
• Strong photosensitivity is a hallmark feature 3
• Seasonal flares are common, particularly in spring and autumn 4

Systemic Involvement

• Joint or muscle pain and occasional arthritis are common 3
• Approximately 29% of SCLE patients meet 4 or more American College of Rheumatology criteria for SLE classification 4
• Serious systemic manifestations such as central nervous system and kidney involvement are rare 3
• Often associated with Sjögren's syndrome 2

Immunological Features

• Anti-Ro/SSA antibodies are present in approximately 71% of cases 4
• Anti-La/SSB antibodies may also be present 3
• Anti-dsDNA antibodies are uncommon (only about 5% of cases) 4
• Immunogenetic predisposition linked to HLA-B8, DR3-phenotype 2
• Direct immunofluorescence typically shows deposits of immunoglobulins and C3 at the dermoepidermal junction in 86% of cases 4

Histopathological Features

• Epidermal atrophy 4
• Hydropic degeneration of the basal layer 4
• Perivascular lymphocytic infiltrate 4
• Dust-like particles in the epidermis are rare (3% of cases) 4

Etiology and Triggers

• Genetic susceptibility factors include:
  • HLA 8.1 ancestral haplotype 1
  • C2, C4 deficiency 1
  • TNF-alpha-308A polymorphism 1
  • C1q deficiency 1
• Environmental triggers:
  • Ultraviolet light exposure 1
  • Photosensitizing drugs/chemicals 1
  • Cigarette smoking 1
  • Infections 1
  • Psychological stress 1
• Drug-induced SCLE:
  • Can be triggered by various medications, particularly those causing photosensitivity 1
  • Typically reported with oral agents, but rare cases of topical medication-induced SCLE have been documented 5

Diagnosis

• Diagnosis requires evaluation by an experienced dermatologist and often a skin biopsy for histological analysis 6
• Follow-up repeat biopsy is recommended if there is a change in the clinical morphology of the lesions or lack of response to treatment 6
• The Cutaneous Lupus Disease Area and Severity Index (CLASI) may be used to assess disease activity and damage 6

Treatment

• Antimalarial drugs (particularly hydroxychloroquine) are the first-line treatment and usually effective 3
• Approximately 75% of patients respond to single agent or combination antimalarial therapy 1
• For resistant cases, additional options include:
  • Glucocorticosteroids 2
  • Diaminodiphenylsulfone (Dapsone) 1
  • Thalidomide 1
  • Retinoids 2
  • Systemic immunosuppressive/immunomodulatory therapy 1
• Sun protection is essential for management 1

Prognosis

• Disease course is characterized by exacerbations and remissions 3
• Generally has a good prognosis regarding life-threatening systemic manifestations 1
• Regular monitoring for development of systemic involvement is recommended 6

Special Considerations

• SCLE may occasionally occur concomitantly with other rheumatological or non-rheumatological diseases 3
• Some cases have been discussed as potentially representing a paraneoplastic syndrome 3
• Neonatal lupus may occur in infants of mothers with anti-Ro/SSA antibodies 6