Eosinophilic folliculitis of the scalp associated with PD‐1/PDL1 inhibitors

Abstract

Background Immune checkpoint inhibitors are monoclonal antibodies which target immune “checkpoints” enhancing T cell–mediated cytotoxic and antitumor responses. Together to the amazing results, these drugs are associated with some peculiar adverse events called immune‐related adverse events. Alopecia is one of these. It is usually reported to be clinically and histologically similar to alopecia areata. Aims We report a case of eosinophilic folliculitis of the scalp occurred during nivolumab therapy, its management and some pathogenetic hypotheses. Patient Herein, we report the first case of eosinophilic folliculitis of the scalp occurred during nivolumab therapy, firstly appeared as a lichen planopilaris. Topical steroids and fusidic acid cream were applied with partial benefit and a scaring outcome. No discontinuation of nivolumab was required. Conclusion Immune checkpoint inhibitors induced inflammatory response leads to the exposure of hair follicle antigens and a consequent loss of Immuno Privilege. We hypothesize a role of steroids in deviating a primarily lichenoid reaction toward a folliculitis.

Eosinophilic pustular folliculitis after phlebectomy: a case report

“…Owen et al 3 describe the case of a patient with EPF that preceded the diagnosis of mantle cell lymphoma. Medications associated with EPF have also been cited in case reports to include PD-1/PDL1 inhibitors, 6 mRNA vaccination for COVID-19, 7 and allopurinol, 8,9 among others. A rare variant of EPF which causes necrotizing lesions has also been reported.…”

“…The patient, in this case, was treated with topical steroids in combination with systemic glucocorticoids and achieved resolution of the condition within 2 months with no recurrence at the time of publication. Medication/vaccination [6][7][8][9] Abbreviation: EPF, eosinophilic pustular folliculitis.…”

Lichen Planopilaris Pemphigoides: A Novel Bullous Dermatosis Due to Programmed Cell Death Protein-1 Inhibitor Therapy

“…23,24 PD-1/PD-L1 inhibitor has been reported to induce LPP. [25][26][27][28][29] However, limited immunogenic evidence was provided in these reports. Therefore, the histological and DIF findings in this case is unlikely to be explained solely by LPP.…”

Mucocutaneous adverse events to immune checkpoint inhibitors

“…Eosinophilic folliculitis after nivolumab leading to scarring alopecia was described in one report (51). Though ICI-induced alopecia is rare (1% for PD-1/PD-L1 inhibitors and 5% for CTLA-4 inhibitors), it can greatly impact quality of life (8,49,50,52). Severe disease may warrant systemic immunomodulators such as JAK inhibitors, though a risk-benefit analysis must be performed to avoid interference with immunotherapy.…”