History and exam
Key diagnostic factors
common
disc-shaped erythematous maculopapular scaly lesions
DLE lesions typically present on the face, neck, scalp, ears, and extensor surfaces of arms.
The lesions usually begin as flat or slightly elevated, well-demarcated, erythematous macules or papules with a scaly surface.
These lesions commonly become larger and coalesce, leading to erythematous plaques with prominent, adherent scale extending into dilated hair follicles.
age 20 to 40 years
The most common age of onset.[4]
history of ultraviolet light exposure
Can precipitate or aggravate DLE lesions, with UV-A and UV-B wavelengths being implicated.
Other diagnostic factors
common
absence of pruritus and/or pain
Characteristically, the lesions are neither painful nor pruritic, but some patients may experience occasional pain within the lesion and/or mild pruritus.
telangiectasia, hyperpigmentation, and/or hypopigmentation
Over time, the lesions slowly expand, producing areas of peripheral inflammation or hyperpigmentation, leaving a central region of scarring with telangiectasia and hypopigmentation.
Hyperpigmentation is a late sign and usually post-inflammatory in white skin but more pronounced in darker skin types. Hypopigmentation may be post-inflammatory or a sign of scarring.
permanent scarring alopecia
If left untreated, DLE scalp lesions inevitably result in alopecia, which becomes permanent once scarring occurs.
uncommon
systemic features (arthritis, pleuritis, pericarditis, seizures, psychosis)
Approximately 5% to 10% of patients develop a mild form of systemic lupus erythematosus (SLE).[2] Therefore, a complete physical examination should be performed to look for signs suggestive of underlying systemic disease, such as arthritis, serositis (pleuritis, pericarditis), central nervous system involvement (seizures, psychosis), or renal involvement.
DLE is considered to have progressed to SLE if systemic features are present and the patient meets the criteria for diagnosis.[13] However, if the patient does not meet diagnostic criteria for SLE, a diagnosis of undifferentiated connective tissue disease is made.
Risk factors
strong
age 20 to 40 years
DLE develops more frequently between the ages of 20 and 40 years; the average peak age of incidence is 38 years.[4]
ultraviolet light exposure
DLE lesions may be precipitated or aggravated by ultraviolet (UV) light exposure, with UV-A and UV-B wavelengths being implicated.
smoking
Several reports have suggested that smoking may predispose to the development of DLE. One study noted a higher smoking prevalence (84.2%) in the DLE group than in the controls (33.5%). Smokers also tend to have more extensive involvement than non-smokers.[8]
weak
female sex
DLE affects both men and women. There is a slightly higher female predominance, with reports of a female-to-male ratio between 3:2 and 2:1 (female-to-male ratio reported as high as 12:1 in systemic lupus erythematosus).[5]
non-specific skin injury
DLE may be precipitated by non-specific injury to the skin (known as the Koebner phenomenon).
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