This is distinguished by affecting all exposed skin, including the forehead and neck, whereas the classic ALE rash is the more defined "malar" or "butterfly" rash.
The key differentiators are the purple (heliotrope) rash on the eyelids and papules over the knuckles (Gottron papules), which are pathognomonic for dermatomyositis and absent in lupus.
This presents as an exaggerated sunburn strictly in sun-exposed areas after starting a new medication and resolves upon drug cessation, unlike the chronic autoimmune nature of lupus.
Eczema is typically more pruritic and scaly, often with a history of atopy, and lacks the sharp demarcation and systemic symptoms (fever, arthritis) that can accompany acute lupus.
This bacterial infection is distinguished by its unilateral presentation, sharp demarcation, warmth, tenderness, and rapid response to antibiotics.
Identified by its characteristic honey-colored crusts, this bacterial infection is superficial and lacks the underlying induration or systemic features of a lupus flare.
This is an overlap of lupus and pemphigus, distinguished by the presence of fragile, crusted erosions on top of the malar rash, confirmed by immunofluorescence.
This common sun allergy is transient, appearing hours to days after sun exposure and resolving within a week, unlike the persistent nature of the lupus rash.
Psoriasis presents with well-defined, silvery-scaled plaques, a morphology very different from the edematous erythema of acute lupus.
Rosacea is distinguished by the presence of papules and pustules (and a lack of comedones), flushing, and the absence of systemic symptoms or positive autoimmune serology seen in lupus.
This is characterized by a greasy, yellowish scale in the nasolabial folds and eyebrows, a different quality of inflammation than the non-scaly erythema of acute lupus.
SCLE presents with distinct annular or papulosquamous plaques, often on the trunk and arms, whereas the rash of ALE is typically a confluent malar erythema.
A simple sunburn is a uniform erythema that corresponds exactly to sun exposure and resolves within days, lacking the specific "butterfly" shape and autoimmune basis of the ALE rash.
