Doxycycline successful in treating patients with idiopathic granulomatous mastitis

The use of doxycycline to treat patients with idiopathic granulomatous mastitis showed promise as a first-line therapy, according to a descriptive case series published in JAMA Dermatology.

“We found that treatment with doxycycline, 100 mg twice daily, was successful as a first-line therapy, with complete response in 50% of patients in the present study,” Alexa B. Steuer, MPH, a research fellow in the department of dermatology at New York University School of Medicine, and colleagues wrote.

Women referred for evaluation of biopsy-proven idiopathic granulomatous mastitis from May 2015 to April 2019 were enrolled in this study. Enrolled patient underwent a comprehensive assessment that included a review of systems and medical history, laboratory workup, chest radiograph, mammogram and breast ultrasonography with core biopsy. All but four patients had bacterial, fungal and mycobacterial tissue cultures obtained.

Clinical improvements were assessed through in-clinic evaluations by one or two researchers, reviewing medical records and clinical photography. Treatment was assessed at initial visit and defined as partial response or complete response.

A total of 32 women were included in the study (mean age, 35.6 years). All 32 patients experienced pain and 70% experienced scarring.

All cultures tested were negative for microorganisms.

There were three patients that were lost to follow-up, and of the 29 remaining patients, 79% were treated with 100 mg doxycycline twice a day. Those who required being treated with methotrexate received 7.5 mg per week, and doses increased as needed.

The mean treatment lengths were 4.6 months for patients being treated with doxycycline and 12.5 months for the methotrexate group. For the doxycycline treatment, 26% of patients failed to have a positive response. In the 16 patients who responded to doxycycline therapy, 50% experienced a complete response and 50% experienced a partial response. Methotrexate was found to be a successful second-line therapy in patients who did not experience positive response to doxycycline.

“This study highlighted the advantage of dermatologic care for this rare condition,” the researchers wrote. – by Erin T. Welsh

Disclosures: Steuer reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.