Updates on Pityriasis Rubra Pilaris: A Scoping Review

Pityriasis rubra pilaris (PRP) is a rare, inflammatory papulosquamous skin disease with unknown exact etiology. Historically, PRP has been challenging to diagnose, especially during the acute phase, and to treat, due to its unclear pathogenesis. To better inform clinical practice, a literature review was conducted employing a broad search strategy to capture PRP-related published studies between January 1, 2012 to October 31, 2022. Two hundred twenty-one studies were identified, which were categorized into 9 themes: (1) potential causes and triggering factors, (2) comorbidities, (3) diagnostic difficulties, (4) genetics, (5) clinical manifestations and laboratory values, (6) treatment, (7) treatment-related adverse events, (8) quality of life, and (9) other. COVID-19 infection, COVID-19 vaccination, and malignancy were the most commonly reported potential triggering factors. Misdiagnosis is very common during the early acute stages. Pathogenesis and genetic studies have further implicated caspase recruitment domain family member 14 (CARD14) mutations in the development of familial PRP (Type V) and have underlined the overlap between psoriasis and PRP. To date, there are currently no specific and validated scoring systems or tools to assess the severity of PRP. While large, randomized trials are still lacking, biologic agents remain the most effective therapy.

Pityriasis Rubra Pilaris: An Updated Review of Clinical Presentation, Etiopathogenesis, and Treatment Options

Pityriasis rubra pilaris (PRP) is a rare papulosquamous reaction pattern with a significant impact on quality of life. Type I PRP is the most common PRP variant, presenting as erythematous papules emerging in a follicular distribution and later coalescing into plaques with characteristic islands of sparing; histologically, an alternating pattern of orthokeratosis and parakeratosis is considered the hallmark of PRP (checkerboard hyperkeratosis). Other PRP variants (types II-V) differ in their age of onset and clinical presentation. Type VI PRP is a rare PRP subtype associated with human immunodeficiency virus infection and is occasionally associated with diseases of the follicular occlusion tetrad. Caspase recruitment domain family, member 14 (CARD14)-associated papulosquamous eruption and facial discoid dermatitis are newly described disease states that have an important clinical overlap with PRP, creating shared conundrums with respect to diagnosis and treatment. The etiology inciting PRP often remains uncertain; PRP has been suggested to be associated with infection, malignancy, or drug/vaccine administration in some cases, although these are based on case reports and causality has not been established. Type V PRP is often due to inborn CARD14 mutations. Furthermore, recent literature has identified interleukin-23/T-helper-17 cell axis dysregulation to be a major mediator of PRP pathogenesis, paving the way for mechanism-directed therapy. At present, high-dose isotretinoin, ixekizumab, and secukinumab are systemic agents supported by single-arm prospective studies; numerous other agents have also been trialed for PRP, with variable success rates. Here, we discuss updates on clinical manifestations, present new insights into etiopathogenesis, and offer a survey of recently described therapeutic options.

Successful treatment with ustekinumab in CARD14-associated papulosquamous eruption in a Brazilian child

CARD14-associated papulosquamous eruption (CAPE) was proposed in 2018 to describe the clinical features of psoriasis and pityriasis rubra pilaris with CARD 14 mutations. We report a 5-month-old female infant who developed CAPE-associated erythroderma. Although she did not respond to conventional therapies, she responded well to ustekinumab treatment at the age of 4 years.

Successful treatment of a child's pityriasis rubra pilaris (PRP) with ustekinumab and acitretin

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease that occurs with phenotypic variability in adults of all ages as well as in children. Data on the treatment of PRP is limited. Here, we report a 5-year-old girl with widespread skin involvement and prominent palmoplantar hyperkeratosis who was initially treated for psoriasis. After reevaluation, a diagnosis of PRP was made, and the patient had an excellent therapeutic response to ustekinumab and acitretin.

Methotrexate Treatment for Pityriasis Rubra Pilaris: A Case Series and Literature Review

Treatment recommendations for pityriasis rubra pilaris (PRP) are based solely on case reports and small case series, as to-date no randomized controlled trials are available. We present here a case series of 3 patients and a literature review of 28 studies treating a total of 116 patients, with the aim of providing data regarding efficacy and safety of methotrexate in the treatment of PRP. Methotrexate was effective in our patients; the review showed an overall response rate of 65.5% with complete clearing in 23.3% and excellent improvement in 17.2%, respectively. After excluding studies with other concurrent systemic therapies or low reliability, the overall response rate increased to 90.9%, with complete clearing in 40.9% and excellent improvement in 31.8%, respectively. Sixteen adverse reactions, of which 11 were mild, were observed in 15 patients (12.9%). In conclusion, the available literature supports good response rates and safety of methotrexate in PRP.

Widespread erythematous skin eruption

The patient presented with a salmon-colored rash from head to toe. The distinctive clinical presentation and a biopsy pointed to an uncommon diagnosis.

[Pityriasis rubra pilaris]

Pityriasis rubra pilaris is a rare heterogeneous disorder characterized by follicular keratosis, perifollicular erythema and palmoplantar hyperkeratosis. The aetiology is still unknown. In the majority of cases some triggering factors are found such as trauma or bacterial infection, possibly on a predisposed condition. In other cases, some immunological disorders are associated, and in familial cases a genetic disorder of keratinization has been suggested. The evolution is variable according to the clinical type. The treatment is not well defined, and there is a lack of clinical trials. The best results however are obtained with oral retinoids, methotrexate or ciclosporine as alternative therapy. New TNF inhibitors and anti-IL-12/23 showed a good result and could be have interest in the future.

Alitretinoin (9-cis retinoic acid) is effective against pityriasis rubra pilaris: a retrospective clinical study

Pityriasis rubra pilaris (PRP) is an uncommon cutaneous disease with disorder of keratinisation. Up to now, systemic retinoids like acitretin or isotretinoin seem to be the most effective therapeutic agents. However, no large trials on this rare disease have been published and no standardised treatment has been established so far. Recently, single case reports demonstrate beneficial effects of alitretinoin (9-cis retinoic acid) in patients with PRP. We performed a retrospective observational analysis of type I adult-onset patients with PRP (n = 5) treated with systemic alitretinoin in our department. Alitretinoin was highly effective in the treatment of PRP in 4 of 5 cases. PASI score was reduced significantly in the alitretinoin responders. We assume that alitretinoin could serve as an additional effective systemic treatment option for type I adult-onset PRP.

Paraneoplastic pityriasis rubra pilaris as the presenting manifestation of metastatic squamous cell carcinoma

Pityriasis rubra pilaris (PRP) is a rare idiopathic papulosquamous eruption. Few cases of PRP have been reported in association with malignancies. We report a case of an 83-year-old Caucasian male who presented with recalcitrant paraneoplastic PRP as the presenting manifestation of metastatic squamous cell carcinoma with unknown primary. Treatment with chemotherapy and radiation led to temporary radiologic and symptomatic regression of the cancer as well as resolution of cutaneous findings. This suggests a direct relationship between the PRP and the underlying malignancy in this patient. This case highlights a rare, but important phenomenon in which PRP may act as a harbinger for underlying malignancy.

[A girl with desquamation of hands and feet]

A 3-year-old girl presented with desquamation of hands and feet, preceded by sore throat and subfebrile temperature. She developed exanthema with typical skip lesions and orange hyperkeratosis. The diagnosis 'classic juvenile pityriasis rubra pilaris' was made. The girl was successfully treated with acitretin.

Systemic sclerosis in a patient with pityriasis rubra pilaris

Pityriasis rubra pilaris (PRP) is a rare, chronic erythematous squamous disorder of unknown etiology. It has been found in association with several autoimmune diseases, including thyroiditis, myositis, myasthenia gravis and vitiligo. Herein we report a case of systemic sclerosis in a patient with classic adult pityriasis rubra pilaris. A 38 year old woman with classic adult type 1 pityriasis rubra pilaris (PRP) developed progressive skin thickening of the trunk, face, upper and lower extremities after 2 years of PRP treatment with topical emollients and steroids. Clinical examination and immunological findings were consistent with SSc. Co-existence of these two rare conditions is documented for the first time.

Pityriasis rubra pilaris: a review of diagnosis and treatment

Pityriasis rubra pilaris (PRP) is a rare inflammatory dermatosis of unknown etiology, and finding a successful therapy can be challenging. PRP occurs equally in men and women. In some patients, associated autoimmune diseases, infections, or malignancies are possible trigger factors. PRP shows a bimodal age distribution, peaking in the first as well as in the fifth to sixth decade. Its classification into five subgroups is based on age at onset, clinical course, morphologic features, and prognosis. More than 50% of patients are best classified as type I with adult-onset PRP. This form is also characterized by high spontaneous remission rates (80%) within 1-3 years. Clinically, the classical adult (type I) and classical juvenile (type III) forms appear to be the same except for the patient's age. Recently, the designation of a new category of PRP (type VI) has been proposed that is characterized by the presence of HIV infection with different clinical features and a poorer prognosis. Typical morphologic features of PRP are erythematosquamous salmon-colored plaques with well demarcated islands of unaffected skin. Often, keratoderma of the palms and soles is present. In patients with extensive disease, ectropion is a dreaded complication. Histology shows hyperkeratosis, alternating orthokeratosis and parakeratosis in a checkerboard pattern, and focal acantholytic dyskeratosis. Descriptions and therapeutic experiences are mainly based on case reports. Mostly, systemic retinoids, methotrexate, and other immunosuppressive agents as well as UV light therapy are applied, with varying response rates. In recent years, treatment with so-called 'biologics' is becoming more and more popular for treating recalcitrant PRP. We present a review of the clinical features, histopathologic findings, classification, differential diagnoses, and treatment of PRP.

Acute juvenile pityriasis rubra pilaris: a case report after mononucleosis infection

A 24-year-old male boy presented dermatosis which first appeared acutely after an infection at age 17. Clinical and histopathologic examinations were consistent with a diagnosis of juvenile pityriasis rubra pilaris type III. Treatment with UVB narrow-band led to complete resolution of the dermatitis within 1 year. Pityriasis rubra pilaris is a papulosquamous disorder of unknown etiology, which can be treated with retinoids, methotrexate, cyclosporine, and narrow-band phototherapy.

Successful treatment of type I adult-onset pityriasis rubra pilaris with infliximab

A 59-year-old woman presented with a painful, pruritic eruption that had commenced as an erythematous, dry patch on the upper back but progressed to erythroderma. Examination revealed orange-tinged erythroderma, scalp scaling, ectropion, palmoplantar keratoderma and nail changes. A diagnosis of type I adult-onset pityriasis rubra pilaris was made, and a subsequent skin biopsy was consistent with this. She was treated with a number of topical and systemic agents with minimal improvement or major side-effects. The patient was then treated with intravenous infliximab 5 mg/kg. She improved dramatically within 2 weeks and was no longer erythrodermic. Five further infusions resulted in additional improvement. Methotrexate was briefly added to the regime, but was ceased owing to nausea. Topical tar and keratolytics were used on the scalp. The patient was left with minimal disease activity and was maintained on emollients.

Circumscribed juvenile-onset pityriasis rubra pilaris with hypoparathyroidism and brachyonychia

Circumscribed juvenile-onset pityriasis rubra pilaris (PRP) manifests as well-defined erythematous scaly plaques with follicular keratosis mainly over the elbows and knees. There are several reports of the association of PRP with other conditions. We report a boy with scattered erythematosquamous skin lesions and follicular hyperkeratotic papules since he was 6 years old. Results of a skin biopsy were compatible with PRP. The patient also had hypoparathyroidism and brachyonychia. To our knowledge, this association has not been reported to date, though minor disturbances of calcium and vitamin D metabolism have been mentioned in some disorders of keratinization. We further discuss the epidemiologic, clinical, and pathologic features of PRP; review the conditions associated with brachyonychia; and give a brief discussion about the possible role of calcium metabolism in disorders of keratinization.

Pityriasis rubra pilaris: a clinical review

Pityriasis rubra pilaris is a skin condition with many different clinical presentations. History, histology, clinical presentation, its different classified forms, treatments, and differential diagnoses are reviewed.

Tinea versicolor mimicking pityriasis rubra pilaris

Tinea versicolor is a common noninvasive cutaneous fungal disease. We recount a case of tinea versicolor that mimicked type I (classic adult) pityriasis rubra pilaris. A 54-year-old white man reported a 20-year history of a recurrent pruritic eruption that had marginally improved with use of selenium sulfide shampoo and treatment with oral antihistamines. Results of a skin examination revealed erythematous plaques; islands of spared skin; and follicular erythematous keratotic papules on the trunk, shoulders, and upper arms. A lesion was scraped to obtain skin scales for potassium hydroxide staining. Examination of the stained samples revealed the characteristic "spaghetti and meatballs," confirming the diagnosis.

[Pityriasis rubra pilaris]

Pityriasis rubra pilaris (PRP) is a rare papulosquamous disease with typical onset during the first and fifth decades. The skin disorder normally starts on the scalp and spreads caudally within a few weeks. It often results in a generalized erythroderma with sharply demarcated islands of sparing ("nappes claires"). A 65-year-old patient with severe PRP showed good clinial improvement after 8 months of treatment when treated with acitretin in combination with phototherapy and systemic gluocorticosteroids.

[Pityriasis rubra pilaris. Case reports and review of the literature]

Various treatment options for pityriasis rubra pilaris (PRP) are evaluated and new aspects of the pathogenesis are reviewed.with. Furthermore, 3 cases of adult onset PRP (type I), treated with acitretin, are presented.

Papulosquamous diseases in the elderly

This article refers to papulosquamous diseases that are seen in the elderly. Many of these diseases are complex to diagnose due to the fact that they are difficult to identify, because they may resemble a similar disorder, which can be misleading. The problem that is frequently seen with these diseases is that they are commonly misdiagnosed. In this article the authors include information that will help with identifying these diseases. The authors also provide important laboratory exams that can be performed and can help guide diagnosis, as well as differential diagnosis and treatment options.

[Paraneoplastic pityriasis rubra pilaris in metastatic adenocarcinoma without diagnosable primary]

HISTORY AND ADMISSION FINDINGS

A 75-year-old woman, without a history of severe illness, developed an erythematosquamous skin disease on hands and forearms. After continued spreading of these cutaneous lesions, she was admitted to hospital, presenting with a generalised desquamating erythrodermia and marked pruritus.

INVESTIGATIONS

Skin biopsy showed cornocutaneous signs with alternating ortho- and parakeratosis, typical for pityriasis rubra pilaris. Laboratory findings showed a chronic to acute inflammation with leukocytosis, granulocytosis in the differential blood count, raised C-reactive protein in a range from 54.7 to a maximum of 157.2 mg/l and a protein electrophoresis with elevated alpha1- and alpha2-fraction.

TREATMENT AND COURSE

The erythrodermia only temporarily receded under systemic therapy with acitretin and prednisolone. The patient developed intermittent septic fever accompanied by reduction or loss of consciousness. The general condition of the patient worsened considerably. Out of a rapidly progressing pleural effusion malignant cells similar to adenocarcinoma were isolated. Because CA15-3 was elevated we conducted an extended search especially for a breast carcinoma, but found only pathologically enlarged axillary, mediastinal and abdominal lymph nodes in conventional X-ray, CT, ultrasound and endoscopic procedures. The patient died from paraneoplastic pulmonary embolism. At autopsy, the widespread metastatic dissemination from poorly differentiated adenocarcinoma was confirmed. A necrosis in the right breast containing tumour cell remnants could probably be regarded as the primary neoplasm. Immunohistochemically no definite proof of breast nor gastro-intestinal carcinoma could be found.

CONCLUSIONS

This case presents a rare paraneoplastic cutaneous manifestation as pityriasis rubra pilaris triggered by a poorly differentiated adenocarcinoma. The primary neoplasm could not definitely be identified, neither pre nor post mortem.

Merkel cell carcinoma and multiple cutaneous squamous cell carcinomas in a patient with pityriasis rubra pilaris

A 79-year-old female was diagnosed with Merkel cell carcinoma (MCC) and multiple cutaneous squamous cell carcinomas (SCC) occurring on a background of pityriasis rubra pilaris. At the time of initial diagnosis and treatment for upper limb MCC, axillary nodal metastases were clinically evident. In the ensuing months, she developed multiple rapidly progressing SCC and eventually a left arm soft tissue deposit of metastatic MCC. Treatment involved multiple courses of fractionated radiotherapy. The salient clinical features and supporting evidence for this case are presented.

Atypical pityriasis rubra pilaris associated with arthropathy and osteoporosis: a case report with 15-year follow-up

Pityriasis rubra pilaris (PRP) is an idiopathic papulosquamous disease that clinically presents with palmoplantar keratoderma and follicular hyperkeratotic papules that coalesce into scaly erythematous plaques. We report a unique case of atypical PRP beginning at 1 year of age with associated severe arthropathy and osteoporosis. We further discuss the clinical and histopathologic aspects of PRP, its possible etiology, and other associated conditions.