What Besides Lupus Can Cause a Butterfly Rash?

Causes of butterfly rash include lupus, rosacea, erysipelas, cellulitis, dermatomyositis, and pellagra.

Lupus is a chronic autoimmune disease that can cause butterfly rash (malar rash), affecting about half of all patients with the disorder. The butterfly-shaped rash on the cheeks and nose can occur spontaneously or after sun exposure. The rash usually appears red and raised, may be scaly, and typically does not affect the nasal folds.  While the rash may occur on its own, it sometimes indicates an oncoming flare-up. 

Though a butterfly rash is often considered characteristic of lupus, other conditions that can cause it include rosacea, erysipelas, cellulitis, dermatomyositis, and pellagra:

• Rosacea
  • The most common cause of butterfly rash 
  • A chronic inflammatory acneiform disease that involves the facial area, especially in middle age
  • This tends to occur in fair-skinned patients.
  • Signs include redness, spider veins, and pustules or papules with no clogged pores.
  • May be accompanied by episodes of flushing triggered by hot drinks, stress, or alcohol
  • Never causes systemic illness 
• Erysipelas
  • A skin infection that includes a painful, rapidly progressive, well-defined, red, shiny plaque accompanied by hair bumps and swelling (peau d'orange)
  • Symptoms include fever, chills, and feeling unwell (malaise).
• Cellulitis
  • A skin infection that involves subcutaneous fat and deeper dermis levels
  • Less well-defined than erysipelas with little or no swelling, and does not usually have systemic symptoms
  • When systemic symptoms occur, they progress slowly.
• Dermatomyositis 
  • An inflammatory muscle condition of unknown cause 
  • Characterized by excess or reduced skin pigmentation, skin atrophy, and spider veins (this grouping of symptoms is called poikiloderma) 
  • Typically occurs on sun-exposed areas of the skin, including the face and eyelids, elbows, knees, knuckles, chest, and back
  • More violet in color in contrast to the poikiloderma in lupus
• Pellagra
  • A systemic disease that results from a cellular niacin deficiency
  • Defined by 4 D's: dermatitis, dementia, diarrhea, and death
  • Occurs on sun-exposed areas of the skin
  • During the acute phase, it may be painful to touch 

Tests used to diagnose lupus or other conditions that can cause butterfly rash include:

• Blood tests 
  • Complete blood count (CBC) with differential
  • Aldolase
  • Antibody tests 
  • Blood clotting time tests 
  • Erythrocyte sedimentation rate (ESR) 
  • C-reactive protein (CRP) levels
  • Complement tests 
  • Creatinine
  • Protein electrophoresis
  • ANA 
  • Anti-double-stranded DNA (anti-dsDNA)
  • Antiphospholipid antibodies (lupus anticoagulant [LA], immunoglobulin [Ig] G and IgM anticardiolipin [aCL] antibodies, and IgG and IgM anti-beta2-glycoprotein [GP] 1)
  • C3 and C4 or CH50 complement levels
  • Urine protein-to-creatinine ratio
  • Serologic studies for infection
  • Rheumatoid factor and anti-cyclic citrullinated peptide antibodies
  • Creatine kinase (CK)
• Urine tests
  • Urinalysis
  • 24-hour urine collection
• Tissue or organ biopsies
• Muscle examination
• Electrocardiography 
• Tests to check for pulmonary embolism 
• Diffusing capacity for carbon monoxide 
• X-rays of swollen joints
• Chest X-rays
• Ultrasound 
• Echocardiography 
• Computed tomography (CT) scan 
• Magnetic resonance imaging (MRI)