# Unilateral Osteonecrosis of the Femoral Head in a Patient with Atopic Dermatitis Due to Uncontrolled Topical Steroid Treatment, a Case Report

## TL;DR

A 29-year-old man developed hip osteonecrosis from long-term uncontrolled use of topical steroids for atopic dermatitis, highlighting a rare but serious side effect.

## Contribution

This case report documents a rare complication of prolonged topical corticosteroid use leading to osteonecrosis of the femoral head.

## Key findings

- Prolonged uncontrolled use of topical mometasone furoate led to stage 3 osteonecrosis of the femoral head.
- Transitioning to upadacitinib improved dermatitis without hip pain flare-ups.
- Total hip arthroplasty was performed due to poor response to prior treatments.

## Abstract

Background and clinical significance: Osteonecrosis of the femoral head (ONFH) is a disease of the epiphysis caused by the death of osteocytes and osteoblasts, resulting in debilitating pain. ONFH can be traumatic or nontraumatic, with prolonged glucocorticoid use being the leading cause of nontraumatic ONFH. Atopic dermatitis (AD) is a chronic inflammatory skin condition typically treated with topical corticosteroids. ONFH following topical corticosteroid treatment is exceedingly rare, with limited documentation in the literature. We present a case of an under-recognized complication of prolonged topical corticosteroid treatment. Case presentation: We report a case of a 29-year-old Caucasian male patient with sharp right hip pain. Plain radiographs, a CT scan, and an MRI indicated Ficat and Arlet stage 3 ONFH. The patient reported the prolonged uncontrolled use of topical mometasone furoate for five years due to AD. Following the diagnosis, topical corticosteroids were discontinued, and the treatment was shifted to tacrolimus and, subsequently, to oral methotrexate with folic acid. The patient underwent a total hip arthroplasty in June 2022. Given his young age and poor response to previous treatments, he was transitioned to upadacitinib, which led to significant improvement without skin flare-ups or postoperative hip pain. Conclusions: This case highlights the rare, but serious, risk of ONFH associated with long-term topical corticosteroid use. It underscores the importance of monitoring systemic side effects in dermatological therapies and educating patients on proper corticosteroid use. Alternative treatments, such as upadacitinib, should be considered in young male patients to prevent severe complications.