Discussion
PRP is an uncommon inflammatory skin condition that shares characteristics with psoriasis and shows heterogeneity in its phenotype.1 The pathophysiology includes triggers such as bacterial or viral infections, autoimmune disorders, neoplasia, and CARD 14 mutations that activate the Th17 pathway. 3 Since this disorder is quite rare and tends to improve spontaneously, it is still challenging to determine the effectiveness of treatment options in clinical trials. 8 As a result, case reports and case series are the primary sources for evaluating treatments, and it may be necessary to try multiple medications to manage the condition effectively. 3,8
Currently, topical treatments are primarily used in children, although they are only effective in mild forms of the disease.9 CsA is one of the medications previously used in PRP. 12, 13 CsA is a medication that suppresses the immune system and targets calcineurin.14 Nephrotoxicity, an increased risk of hypertension, hypertrichosis, and gingival hyperplasia are among the side effects that have been seen during treatment. In clinical practice, CsA is administered at a dose of 2.5 to 5.0 mg/kg per day, and most patients show improvement after 8 weeks of treatment. 14 The exact mechanism of action of CsA for PRP and its efficacy is still unclear. The histological changes observed in PRP align with a proliferative pattern of keratinocytes. Moreover, Marsili et al.15 found that CsA may suppress keratinocyte growth in vitro. It has been demonstrated that CsA is a very successful medication for treating severe inflammatory dermatoses in children.16 However, using CsA for treating PRP is still limited, and there are conflicting findings in various case reports regarding its effectiveness. To the best of our knowledge, 11 case reports involving 13 patients, have evaluated the efficacy of CsA in treating juvenile PRP (Table 1). Among these cases, three patients, including our patient, showed complete clearance of symptoms after a short course of CsA (mean duration: 16.67 ± 4.16 weeks), without any reported adverse effects or relapses. All these three patients were diagnosed with PRP type III, and the mean age of onset was 2.33 ± 1.44 years. 17,18 Five cases reported a partial response to CsA, 19, 20, 21while CsA was ineffective in two cases. 22,23 In one case a good response to CsA was reported initially, but unfortunately, it was discontinued due to disease recurrence and concerns about side effects. 24Overall, a total of 23% of cases demonstrated a complete response to CsA, which is consistent with a previous case series of 28 patients with adult-onset PRP. 25 None of the reported cases mentioned any adverse effects during treatment with CsA.
In the present case, there was a complete clearance after 2 months of low-dose CsA therapy. There was no increase in blood pressure or any negative impact on renal function during the treatment. Furthermore, there was no recurrence of PRP over more than 3 months of follow-up after the cessation of CsA. Since potential side effects of CsA therapy typically appear after prolonged use, short-term therapy appears to be safe.
It is challenging to determine the effectiveness of treatment options for pityriasis rubra pilaris (PRP) due to its rarity and tendency to improve spontaneously. In this study, we reviewed using CsA as an alternative treatment option for juvenile-onset PRP. The results of this study were consistent with previous findings for adult-onset PRP. We recommend considering the use of CsA as an alternative option for a short period to treat juvenile-onset PRP.