Combination of Oral Hydroxychloroquine and Topical Pimecrolimus 1% for Linear Morphea in Breastfeeding: A Rare Case with Favorable Outcome.

Background: Linear morphea (LM) is a chronic autoimmune disease characterized by linear or band-like localized sclerosis that may involve the dermis, subcutaneous tissue, muscle, and underlying bone. While LM typically presents in childhood, adult-onset disease is considerably less common, and LM presenting during breastfeeding has not, to our knowledge, been previously documented. As a result, therapeutic guidance for managing LM in breastfeeding women remains extremely limited, highlighting the need for additional clinical evidence in this population. Case Presentation: A 44-year-old breastfeeding woman presented with brownish-white skin lesions with a line configuration and hardened skin on the right shoulder, upper arm, forearm, hand, and fingers. The histopathological findings demonstrated epidermal thinning with flattened rete ridges, thickened fibrocollagenous connective tissue stroma extending into the subcutaneous fat, hyaline degeneration, a mild lymphocytic inflammatory, and absence of pilosebaceous unit. The laboratory analysis revealed a positive ANA test with a titer of 1:320 and the presence of anti-RNP and anti-Sm autoantibodies. The patient received hydroxychloroquine (HCQ) 200 mg twice daily and topical pimecrolimus 1% cream twice daily. After three months of observation, there was an improvement in the skin lesions. In addition, the modified localized skin index (mLoSSI) score and the localized scleroderma damage index (LoSDI) score decreased from 6 to 1 and 5 to 4, respectively. No adverse effects related to retinal toxicity were reported during the course of therapy. Conclusion: This case suggests that the combination of oral HCQ and topical pimecrolimus may represent a safe and effective therapeutic option for LM in breastfeeding women, although further evidence is needed to confirm long-term outcomes.