Dupilumab and the Development of a Halo Nevus: A Case of Immune Shift
A rare skin phenomenon sheds light on the immune-shifting effects of dupilumab therapy in atopic dermatitis
Key Takeaways
Dupilumab may shift immune balance from a Th2-dominant to Th1/Th17 response, potentially triggering pigmentary changes.
This is the first documented case of a halo nevus developing on a congenital melanocytic nevus (CMN) during dupilumab treatment.
Halo nevi are uncommon, especially when seen on CMN, and may be mistaken for melanoma regression.
Clinicians should be aware of immune-related pigmentary changes, such as vitiligo and halo nevi, in patients on dupilumab.
What happens when an eczema treatment alters immune signaling so much that it accidentally targets pigment cells? A recently published case report in JAAD Case Reports describes the first known case of a halo nevus developing on a congenital melanocytic nevus (CMN) during dupilumab therapy, offering a fascinating clue into this immune-mediated phenomenon.
Case in Focus
A 6-year-old boy with moderate atopic dermatitis had recently begun treatment with dupilumab. Nearly a year into therapy, his mother noticed a white halo forming around a congenital melanocytic nevus (CMN) on his buttock. Along with the depigmented rim, the central nevus also began to lose pigmentation, and the hairs within it turned white.
Examination confirmed a 4.5 × 2.5 cm pigmented patch surrounded by a broad depigmented halo, consistent with a halo nevus. No biopsy was performed due to classic clinical presentation. A Wood’s lamp exam showed no other areas of depigmentation.
Understanding the Halo Phenomenon
Halo nevi are characterized by an immune-mediated ring of depigmentation surrounding a melanocytic nevus. They are most often seen in children and adolescents, but their appearance over congenital nevi is extremely rare.
The halo effect is thought to occur when cytotoxic T cells and autoantibodies target melanocytes in the nevus and surrounding skin, leading to pigment loss. While usually benign, this reaction can mimic regressing melanoma, underscoring the importance of careful evaluation.
Dupilumab’s Role?
Dupilumab blocks the IL-4 receptor alpha, dampening the Th2-driven inflammation seen in atopic dermatitis. But this suppression can cause a compensatory immune shift toward a Th1/Th17 profile—an immune signature often implicated in autoimmune depigmenting disorders like vitiligo.
Indeed, vitiligo has already been reported in at least eight dupilumab-treated patients. This case suggests that halo nevi may be part of that same immune-driven pigmentary spectrum.
Clinical Takeaway
This case highlights an unusual, but potentially under-recognized, cutaneous side effect of dupilumab. While more research is needed, clinicians should be aware of pigmentary changes that may arise during biologic therapy, especially as dupilumab continues to be used in a growing number of inflammatory skin diseases.
References
Camuñas, J. C., Sacarello, I. J., & Fontánez, F. C. (2025). Halo phenomenon on a congenital melanocytic nevus after dupilumab. JAAD Case Reports.