Case Report
A 69-year-old woman diagnosed with breast cancer 4 years prior to her presentation to dermatology initially underwent a lumpectomy and radiation treatment. She was subsequently started on anastrozole 2 years later. After 16 months of treatment with anastrozole, she developed an erythematous scaly rash on sun-exposed areas of the skin. The patient was seen by an outside dermatologist who treated her for a patient-perceived drug rash based on biopsy results that simply demonstrated interface dermatitis. She was treated with both topical and oral steroids with little improvement and therefore presented to our office approximately 6 months after starting treatment seeking a second opinion.
Figure 1. Erythematous scaly papules and plaques in a photodistributed pattern on the back (A), right arm, and chest (B).
Figure 2. Histopathology at presentation showed an inflammatory infiltrate on low-power (A) and high-power magnification (B)(H&E, original magnifications ×10 and ×40).
Figure 3. Drug-induced subacute cutaneous lupus erythematosus on the back (A) and right arm (B) improved 1 month following treatment with hydroxychloroquine.
Physical examination revealed numerous erythematous scaly papules and plaques in a photodistributed pattern on the chest, back, legs, and arms (Figure 1). On further questioning, the patient noted that the rash became worse when she was at the beach or playing tennis outside as well as under indoor lights. A repeat biopsy was performed, revealing interface and perivascular dermatitis with an infiltrate composed of lymphocytes, histiocytes, and scattered pigment-laden macrophages (Figure 2). Given the appearance and distribution of the rash as well as the clinical scenario, drug-induced lupus was suspected. Anastrozole was the only medication being taken. Laboratory evaluation was performed and was negative for antinuclear antibodies, antihistone antibodies, and anti-La/SS-B antibodies but was positive for anti-Ro/SS-A antibodies (>8.0 U [reference range, <1.0 U]). Based on these findings, anastrozole-induced SCLE was the most likely explanation for this presentation. The patient was started on a sun-protective regimen (ie, wide-brimmed hat, daily sunscreen) and anastrozole was discontinued by her oncologist; the combination led to moderate improvement in symptoms. One week later, oral hydroxychloroquine 200 mg twice daily was started, which led to notable improvement (Figure 3). The patient was seen for 2 additional follow-up visits, each time with sustained resolution of the rash. The hydroxychloroquine was then stopped at her last visit 3 months after diagnosis. The patient was subsequently lost to follow-up.