Type I Pityriasis Rubra Pilaris: Upregulation of Tumor Necrosis Factor α and Response to Adalimumab Therapy

Background: Pityriasis rubra pilaris (PAP) has unknown etiology and is often refractory to conventional therapies. Objective: To document a PRP patient's response to adalimumab therapy and to highlight the potential role of tumor necrosis factor (TNF) in the development of PAP skin lesions. Methods: A patient received adalimumab therapy at standard dosing intervals. In addition, the messenger ribonucleic acid (mRNA) of TNF in the lesional and perilesional normal skin was quantified in two patients with PAP. Results: The patient responded to adalimumab therapy and achieved clinical remission by 4 months. There was a significant elevation of TNF mRNA in the lesional skin of PAP. Conclusion: TNF upregulation is detected in PRP lesional skin, consistent with the observed clinical efficacy of TNF blockade for the treatment of PRP.