Differential Diagnosis for Unilateral Malar Rash
- Single Most Likely Diagnosis
- Lupus erythematosus: This is the most common cause of a malar rash, which is a characteristic "butterfly-shaped" rash across the cheeks. Although it is typically bilateral, it can occasionally present unilaterally.
- Other Likely Diagnoses
- Dermatomyositis: This is an inflammatory disease characterized by skin rash and muscle weakness. The rash can be similar to a malar rash and may be unilateral.
- Rosacea: A chronic skin condition characterized by facial redness, swelling, and small, pus-filled bumps. It can cause a unilateral malar rash, especially if it is localized to one side of the face.
- Contact dermatitis: This is a type of skin inflammation caused by contact with irritants or allergens. It can cause a unilateral malar rash if the irritant or allergen comes into contact with one side of the face.
- Do Not Miss Diagnoses
- Erythema multiforme: A skin condition characterized by target-shaped lesions, which can be a sign of a life-threatening condition such as Stevens-Johnson syndrome. Although it is typically bilateral, it can occasionally present unilaterally.
- Cellulitis: A bacterial skin infection that can cause redness, swelling, and warmth of the skin. If left untreated, it can lead to serious complications, such as sepsis.
- Rare Diagnoses
- Sarcoidosis: A condition characterized by the growth of granulomas (inflammatory cells) in various parts of the body, including the skin. It can cause a unilateral malar rash, although this is a rare presentation.
- Granuloma faciale: A rare skin condition characterized by a chronic, inflammatory lesion on the face, which can cause a unilateral malar rash.