Apremilast: A Novel and Effective Therapy for Pityriasis Lichenoides Chronica

Dear Editor, Pityriasis lichenoides (PL) is an inflammatory papulosquamous dermatosis of unknown etiology. It has two variants: pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica (PLC).[1] PLC presents with multiple scaly, erythematous to brown papules predominantly on the trunk and extremities. It typically follows a chronic relapsing-remitting course lasting for months to years. Treatments for PLC include phototherapy, oral erythromycin, oral tetracyclines, and methotrexate with variable results.[2] The use of apremilast in the treatment of PLC has not been reported in the literature. In the present case of PLC, we found an excellent response with oral apremilast, suggesting a potential new role for the phosphodiesterase (PDE)-4 inhibitor in its management. A 25-year-old male presented with recurrent crops of reddish itchy lesions on the trunk for 2 months. Despite several courses of antibiotics and antifungals from private practitioners, there was no improvement. There was no history of fever, cold, cough, or any drug intake prior to the onset of lesions. Cutaneous examination revealed multiple erythematous to brownish papules with loosely adherent fine scaling on the trunk and proximal part of extremities, sparing face, palms, soles, and mucosa. Few lesions healed with hypopigmentation [Figure 1].Figure 1: Multiple erythematous to brownish papules with loosely adherent fine scaling on the trunk and proximal part of extremities, few lesions healed with hypopigmentationFigure 2: Histopathology (Hematoxylin and Eosin stain, 100×) showing parakeratosis, acanthosis, mild spongiosis, lymphocytic exocytosis, basal cell vacuolar degeneration and moderate perivascular lymphocytic infiltrate in the dermisSkin biopsy from a lesion showed parakeratosis, acanthosis, mild spongiosis, lymphocytic exocytosis, basal cell vacuolar degeneration, and moderate perivascular lymphocytic infiltrate in the dermis. These findings were consistent with PLC [Figure 2]. The venereal disease research laboratory (VDRL) test was negative. The patient was treated with oral erythromycin 500 mg 4 times daily for 4 weeks, and subsequently with minocycline 100 mg once daily for the next 2 weeks, with minimal improvement. Hence, the patient was started on apremilast 20 mg twice daily. After 1 week, he experienced a significant reduction in itching, and the lesions started healing. Two weeks after starting apremilast, there was 90% improvement in the lesions [Figure 3]. Patient was continued on the same dose of apremilast for 1 month; after which, he was lost to follow-up.Figure 3: Two weeks after apremilast, 90% improvement in the lesionsPLC is most commonly seen in young adults. Although PLC is benign, its recurrent course with scaly, itchy lesions is distressing to the patients. At present, phototherapy and topical steroids are considered the first-line treatments, followed by oral erythromycin and methotrexate. Apart from these, oral minocycline, azithromycin, and acyclovir have been tried with variable success. In our case, the patient was initially treated with oral erythromycin and oral minocycline, which are considered first-line treatments. Due to minimal response to these agents and the patient’s unwillingness to use methotrexate and phototherapy, we considered apremilast, an anti-inflammatory agent with a good safety profile. The exact pathogenesis of PL remains unclear. There is abnormal proliferation of T-cells secondary to exogenous stimuli such as infections or drugs.[3] Apremilast is a PDE-4 inhibitor that works by increasing the intracellular cyclic adenosine monophosphate (cAMP) and decreasing the production of multiple pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-5, IL-8, IL-12, which activate T-cells.[4,5] This inhibitory action of apremilast on T-cell proliferation was the rationale behind the use of apremilast in this case. At present, the exact cytokine profile that activates the T-cell proliferation in PLC is not known. The clinical response was rewarding, with a marked reduction in pruritus within 1 week and rapid resolution of lesions over 2 weeks. The response highlights apremilast’s robust anti-inflammatory potential in PLC, mirroring its efficacy seen in other papulosquamous inflammatory dermatoses such as psoriasis and lichen planus, with minimal side effects.[4,5] Hence, it can be considered as a potential alternative in the treatment of PLC. The present case demonstrates the novel and effective use of apremilast in the management of PLC. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. Use of artificial intelligence (AI) The preparation of this manuscript was carried out entirely by the authors without the use of artificial intelligence technologies.