Pitiriasis rubra pilaris aguda postinfecciosa: una dermatosis mediada por superantígenos

Loss-of-function mutations in Keratin 32 gene disrupt skin immune homeostasis in pityriasis rubra pilaris

Pityriasis rubra pilaris (PRP) is an inflammatory papulosquamous dermatosis, characterized by hyperkeratotic follicular papules and erythematous desquamative plaques. The precise pathogenic mechanism underlying PRP remains incompletely understood. Herein, we conduct a case-control study involving a cohort of 102 patients with sporadic PRP and 800 healthy controls of Han Chinese population and identify significant associations (P = 1.73 × 10-6) between PRP and heterozygous mutations in the Keratin 32 gene (KRT32). KRT32 is found to be predominantly localized in basal keratinocytes and exhibits an inhibitory effect on skin inflammation by antagonizing the NF-κB pathway. Mechanistically, KRT32 binds to NEMO, promoting excessive K48-linked polyubiquitination and NEMO degradation, which hinders IKK complex formation. Conversely, loss-of-function mutations in KRT32 among PRP patients result in NF-κB hyperactivation. Importantly, Krt32 knockout mice exhibit a PRP-like dermatitis phenotype, suggesting compromised anti-inflammatory function of keratinocytes in response to external pro-inflammatory stimuli. This study proposes a role for KRT32 in regulating inflammatory immune responses, with damaging variants in KRT32 being an important driver in PRP development. These findings offer insights into the regulation of skin immune homeostasis by keratin and open up the possibility of using KRT32 as a therapeutic target for PRP.

Treatment Options for Juvenile Pityriasis Rubra Pilaris

Pityriasis rubra pilaris represents a group of familial and acquired disorders of cornification that affect both adult and pediatric patients. Treatment options are difficult to assess through clinical trials, given the rarity of the disorder and its tendency for spontaneous remission. Case reports and case series are therefore the primary means of assessment. Because of the heterogeneity of the disease, there is no universal approach to treatment, and multiple agents may need to be trialed to achieve disease control. At present, topicals are used for most pediatric patients, though monotherapy with topicals is only effective for less severe disease. Despite concerns over their side-effect profiles, oral retinoids are generally accepted as a first-line systemic therapy. However, interleukin-17 inhibitors and ustekinumab, an interleukin-12 and interleukin-23 inhibitor, may soon become first-line systemic treatment as well, given their efficacy and relative safety in trials thus far. Ustekinumab, in particular, is emerging as a first-line agent for patients with pityriasis rubra pilaris with CARD14 gene variations. When these therapies fail, second-line and adjunctive therapies to consider include tumor necrosis factor-alpha inhibitors, methotrexate, and phototherapy. However, further investigation is necessary to assess the safety and efficacy of many of these agents in juvenile pityriasis rubra pilaris.

Pityriasis rubra pilaris post-infection due COVID-19: case report

Case description:

32-month-old boy, IgG positive for SARS-CoV-2, presented to the emergency department with dermatologic lesions.

Clinical findings:

Four days before admission, he presented skin eruptions with redness and pruritus on hands and feet. Generalized papular erythema was evidenced, upper extremities with diffuse erythematosquamous plaques, palmoplantar keratoderma, so he was evaluated by a dermatologist who diagnosed pityriasis rubra pilaris.

Treatment and outcome:

rehydrating cream, cetirizine 0.5 mg/kg/day every two days, and prednisolone 2 mg/kg/day in the morning. He was discharged after 14 days, the patient presented clinical improvement, but the erythematous lesion persisted on the trunk and extremities. In the evaluation, after three months, the patient did not show the described lesions, evidencing an improvement and clinical resolution of the dermatological problems.

Clinical relevance:

We report a patient with pityriasis rubra piloris associated with a post-infection by SARS-CoV-2 that had not been described before.

Recurrent Pityriasis Rubra Pilaris: A Case Report

Pityriasis rubra pilaris (PRP) is an uncommon papulosquamous dermatosis characterized by follicular, erythematous, hyperkeratotic papules coalescing to salmon-coloured plaques with islands of sparing. The disease tends to be self-limited and resolves spontaneously after a few years. In some cases, the disease is persistent. However, recurrence of this disease has rarely been described. An 8-year-old male was diagnosed with type III (classic juvenile) PRP. He was treated with acitretin, and his skin was clear after 6 months. He remained disease free for 6 years. At 14 years old, he was diagnosed again with type III PRP. His cutaneous manifestations were highly similar to his initial presentation. He was treated with acitretin and methotrexate concurrently and achieved skin clearance. Recurrence of type III PRP is possible although rarely described in the literature. Acitretin ± methotrexate therapy is effective at achieving skin clearance.

An unusual cluster of circumscribed juvenile pityriasis rubra pilaris cases

Circumscribed juvenile pityriasis rubra pilaris (PRP) is an uncommon dermatosis. We describe the unusual clustering of circumscribed juvenile PRP cases in our pediatric dermatology clinic in 2011. A retrospective chart review was done of patients presenting during the summer of 2011 with classic findings of circumscribed juvenile PRP. Clinical data including past medical and family history, presenting symptoms, infectious disease history and evaluation, biopsy results, and management were recorded. Seven patients, ages 5 to 19 years, all had strikingly similar skin findings of pink to hyperpigmented, well-defined, scaly papules and plaques on their elbows, knees, dorsal hands, ankles, and Achilles tendons. Four of the seven also had palmoplantar involvement. Four were sibling pairs and the other three were unrelated. Streptococcus pyogenes infection was suspected as a trigger in four of the patients. The unusual clustering of this uncommon disease, along with the occurrence in two sibling pairs, suggests that a genetic susceptibility unmasked by an infectious agent may play a role in its pathogenesis.