Differential includes rosacea and seborrheic dermatitis
The diagnosis of MF can be difficult as it often imitates other benign inflammatory conditions.
Rosacea manifests as an erythematous facial rash but usually spares the nasolabial folds and eyelids. There are several forms, including ocular (featuring swollen and irritated conjunctiva), erythematotelangiectatic (with visible blood vessels), and papulopustular (with acneic lesions). Over time, the skin may develop a thickened, bumpy texture, referred to as phymatous rosacea.4 A history of acute worsening with exposure to certain hot or spicy foods, alcohol, or ultraviolet light suggests a diagnosis of rosacea.
Seborrheic dermatitis classically presents as yellow scaling on a mildly erythematous base and often involves nasolabial folds and eyebrows. Seborrheic dermatitis can be associated with human immunodeficiency virus, Parkinson’s disease, and other chronic medical conditions.
Allergic contact dermatitis can look identical to MF, but in our case, there was no new allergen in the history. A thorough history regarding new medications, creams, and household supplies is integral to differentiating this diagnosis.
Misdiagnosis can lead to advanced-stage disease
This case of persistent facial erythema, originally treated as rosacea, highlights the importance of having a low threshold of suspicion of MF, especially in a patient with a prior history of MF. A recent study by Kelati et al3 indicated that certain subtypes of MF are easily misdiagnosed and treated as psoriasis or eczema respectively for an average of 10.5 years.3 These years of misdiagnosis are significantly correlated with the development of advanced-stage MF, which is more difficult to treat.3
Continue to: Treatment with topical desonide and mechlorethamine