Lupus is distinguished by its classic "butterfly" rash that spares the nasolabial folds and lacks the pathognomonic eyelid (heliotrope) and knuckle (Gottron) signs of dermatomyositis.
This is an eczematous reaction to airborne allergens, lacking the characteristic violaceous hue, muscle weakness, and specific signs (Gottron, heliotrope) of dermatomyositis.
While it can cause a photosensitive rash, CTCL presents with patches and plaques that are often bizarrely shaped and atrophic, a different morphology than the edematous rash of dermatomyositis.
DLE is characterized by scarring, atrophic plaques with follicular plugging, a different presentation than the non-scarring, violaceous rash of dermatomyositis.
This is an acute, sunburn-like reaction to a drug and lacks the specific periorbital and hand findings of dermatomyositis.
Eczema is a scaly, pruritic dermatitis that lacks the characteristic purple color and specific distribution (eyelids, knuckles, V-neck) of dermatomyositis.
This rare systemic disease is distinguished by its destructive arthritis and characteristic "coral-bead" papules around the nail folds.
Psoriasis presents with well-demarcated, silvery-scaled plaques, which is morphologically distinct from the violaceous erythema of dermatomyositis.
Rosacea is characterized by papules, pustules, and flushing in a central facial distribution, without the muscle weakness or pathognomonic signs of dermatomyositis.
Scleroderma is defined by skin hardening and fibrosis (sclerosis), a very different cutaneous finding than the inflammatory rash of dermatomyositis.
Topical steroid overuse leads to skin atrophy and telangiectasias, not the primary inflammatory rash of dermatomyositis.
SCLE presents with distinct annular or papulosquamous plaques, which is a different morphology than the confluent, violaceous erythema of dermatomyositis.
This parasitic infection can cause periorbital edema and muscle pain, but it is distinguished by a history of ingesting undercooked pork and marked peripheral eosinophilia.
