Pityriasis rubra pilaris and human immunodeficiency virus infection

Emerging Role of Biologic Drugs Targeting IL-17 and IL-23: Pityriasis Rubra Pilaris

Pityriasis rubra pilaris (PRP) is a rare, papulosquamous, inflammatory skin disease. PRP represents a therapeutic challenge. The rarity of this disease and its possible spontaneous remission makes the conduction and interpretation of therapeutic studies particularly difficult. Moreover, PRP not infrequently proves resistant to common topical and conventional systemic therapies. In this context, numerous biologic agents have been reported in PRP treatment. The aim of our manuscript was to review the current literature to evaluate the possible role of biologics targeting the IL17/23 axis in PRP management. Recent cases in the literature have highlighted the use of several promising drugs: IL-17 inhibitors, IL-23 inhibitors, and the IL-12/23p40 inhibitor ustekinumab. However, it should be noted that all these drugs are approved for moderate-to-severe plaque psoriasis and their use in PRP is off label. The treatment of PRP is based on clinical experience, case reports or case series reported in the literature, as randomized controlled trials are difficult to conduct due to the rarity of the condition. Despite data on the efficacy of drugs targeting IL-17 and IL-23 being promising, they are still limited. Certainly, further studies are desirable to better characterize PRP and establish shared guidelines.

HIV: Inflammatory dermatoses

Patients living with HIV may experience a variety of inflammatory dermatoses, ranging from exacerbations of underlying conditions to those triggered by HIV infection itself. This article presents a current literature review on the etiology, diagnosis and management of atopic dermatitis, psoriasis, pityriasis rubra pilaris, lichen planus, seborrheic dermatitis, eosinophilic folliculitis, pruritic papular eruption and pruritus, in patients living with HIV.

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 of Pityriasis Rubra Pilaris with Risankizumab in Children

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease that affects men and women of all ages, including children. PRP is characterized by follicular and palmoplantar hyperkeratosis and salmon-colored scaling plaques. The exact pathogenesis of PRP is still unknown; most PRP cases are acquired, but some cases may show a familial occurrence, often associated with a mutation in the CARD14 gene. Due to the rarity of PRP, treatment recommendations are based mainly on case reports, small case series and expert opinions and still represent a major therapeutic challenge, especially in children. A growing number of reports on treatment with biologicals, particularly anti-TNFα, has been published. However, an involvement of the IL-23/Th17 axis in both psoriasis and PRP pathogenesis may suggest that this pathway may be a potential therapeutic target. Here, we present three pediatric patients with PRP successfully treated with risankizumab. All patients exhibited a severe course of PRP and lack of response to conventional therapy, including acitretin, cyclosporine and phototherapy. A single dose of 75 mg risankizumab resulted in almost complete clearance of skin lesions in case 1 and 2 at week 4. In patient 3, clear skin was achieved after the second administration of risankizumab (150 mg). All patients continue the treatment with risankizumab, and no adverse effects have been reported up to the present time. Our study demonstrates that risankizumab, an IL-23 blocker, shows good efficacy and safety among pediatric patients with PRP.

A Rare Post-infectious Rash: Pityriasis Rubra Pilaris After COVID-19 Infection

Pityriasis rubra pilaris (PRP) is a rare papulosquamous skin disorder that often presents with erythematous follicular-based hyperkeratotic papules that can become confluent and lead to erythroderma and electrolyte and thermoregulatory imbalances resulting from increased tissue perfusion and skin barrier breakdown. Due to this condition being uncommon, many specialties outside of dermatology are unfamiliar with this entity which poses unique diagnostic and management challenges. This case report involves a 55-year-old woman who presented to the emergency room with erythroderma secondary to PRP. It highlights the relevance of PRP in the context of in-hospital management by presenting the patient's clinical profile, diagnostic workup, and treatment plan. By emphasizing the distinctive clinical features and natural course of the disease, this report aims to enhance the understanding of this uncommon inflammatory skin condition.

Evaluation of Ixekizumab Treatment for Patients With Pityriasis Rubra Pilaris: A Single-Arm Trial

Importance

Pityriasis rubra pilaris is a rare and disabling cutaneous disease that is frequently recalcitrant to conventional therapies and appears to involve interleukin (IL)-17 overexpression.

Objective

To investigate the clinical response and safety of ixekizumab in treating pityriasis rubra pilaris.

Design, Setting, and Participants

Single-arm, investigator-initiated trial conducted in adult patients with moderate to severe pityriasis rubra pilaris at a single-center academic university from June 2018 to January 2020. A total of 41 patients were screened, 12 were enrolled, and 11 completed the full duration of therapy. A referred, consecutive sample was used during participant selection. The treatment period and primary outcome occurred over 24 weeks with additional patient follow-up through 36 weeks.

Intervention

Subcutaneous administration of ixekizumab, a humanized IgG4 antibody that binds IL-17A, at the US Food and Drug Administration-approved dosing schedule for treatment of psoriasis for 24 weeks.

Main Outcomes and Measures

The primary outcome was the mean change in Psoriasis Area and Severity Index at 24 weeks. Secondary outcomes included change in affected body surface area, quality of life, induction of sustained remission, and association of improvement with CARD14 genetic variations and cutaneous cytokine expression.

Results

A total of 12 white patients (mean [SD] age, 49.8 [15.1] years; 8 male [67%]) were enrolled between June 2018 and April 2019, with 11 completing the full course of intervention. The mean (SEM) improvements in Psoriasis Area and Severity Index, affected body surface area, and Dermatology Life Quality Index were 15.2 (2.1) (P < .0001), 29.8% (9.3%) (P = .009), and 9.5 (2.5) (P = .004), respectively. The 4 participants with the most improvement in Psoriasis Area and Severity Index at week 24 stayed in remission at week 36 (defined as lack of increase in Psoriasis Area and Severity Index from week 24 through week 36), off therapy. Relative dermal IL-17A expression decreased by a 1.9 log-fold change. No participants had known pathogenic CARD14 variations. There were no serious adverse events.

Conclusions and Relevance

In this single-armed trial, ixekizumab was associated with reduced clinical signs and symptoms of pityriasis rubra pilaris in a subset of patients, including those in whom other systemic therapies have failed.

Trial Registration

ClinicalTrials.gov Identifier: NCT03485976.

Pityriasis rubra pilaris type 6: A case report in an AIDS patient

A 24-year-old woman, known to be human immunodeficiency virus positive for 6 years, presented with an itchy rash on the body. She had dull erythematous to hyperpigmented scaly plaques over the body, with extensor predominance. Inflammatory papules and nodules were noted on the face. Follicular hyperkeratotic papules were seen on the shins, giving a “nutmeg grater” feel. All her nails were dystrophic. Histopathology was consistent with the clinical diagnosis of pityriasis rubra pilaris. CD4 counts had dropped to 192 cells/μl, so she was started on antiretroviral therapy along with acitretin to which she responded well within 2 months.

Pityriasis in dermatology: an updated review

Dermatology has a very distinctive lexicon. The term pityriasis refers to several dermatologic conditions which all feature scaling of the skin. According to the Merriam-Webster dictionary, the term pityriasis was first used in print in 1684. Although the diseases beginning with the name pityriasis are of diverse causation, they do represent important dermatologic diseases, with some common and others quite rare. It is important for dermatologists to be aware and updated on all pityriasis conditions in dermatology.

Paraneoplastic pityriasis rubra pilaris in association with prostate carcinoma: A case report and literature review

Pityriasis rubra pilaris (PRP) is a chronic papulosquamous disorder of unknown etiology, characterized by reddish orange scaly plaques, islands of sparing, palmoplantar keratoderma, and keratotic follicular papules. The disease can be acquired or inherited, being divided into 5 categories: classic adult type, atypical adult type, classic juvenile type, circumscribed juvenile type, and atypical juvenile type. More recently, an HIV-associated type has been added to this classification. The cases of PRP associated with malignancy are unusual. We present a case of a 58-year-old man, with the typical clinical aspect of PRP with a four-month onset of the disease. The histopathological and dermatoscopical findings confirmed the PRP diagnosis. The routine laboratory results were in normal limits, except the number of eosinophils, which was elevated and the number of lymphocytes, which was lower. After a thorough examination within a hematological consultation, the cause of hypereosinophilia remained unknown. An imagistic examination was performed and a prostate hypertrophy was noted. The prostate-specific antigen (PSA) level was found to be increased. The urologic consultation based on clinical, imagistic and microscopic features diagnosed an early stage prostate carcinoma. The conclusion was a paraneoplastic PRP in association with prostate carcinoma. The search in international databases revealed twelve published cases regarding the association of PRP with malignancies. The presented case represents a rare coexistence of PRP with malignancy, particularly with prostate carcinoma, and indicates that PRP can occur as paraneoplastic dermatosis, heralding a malignancy. This case is the first one to present PRP associated with prostate carcinoma. Nonetheless, in the authors' opinion, PRP can be considered a paraneoplastic syndrome; therefore, tumor screening is mandatory in cases presenting this disease.

Pityriasis rubra pilaris as a systemic disease

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disorder of unknown etiology, initially described in 1835. It is characterized by keratotic follicular papules, well-demarcated salmon-colored erythematous scaly plaques interspersed with distinct islands of uninvolved skin, and palmoplantar keratoderma. Is PRP a systemic disease? Skin is mainly affected in PRP. Despite its clinical heterogeneity, PRP could be associated with a variety of rheumatologic, infectious, neoplastic, and other extracutaneous manifestations. We accept the hypothesis of not only an association but also a causative relation between skin and systemic manifestations with possible common underlying pathomechanisms such as systemic immunologic processes and superantigen mimicry.

Systemic therapies of pityriasis rubra pilaris: a systematic review

Pityriasis rubra pilaris (PRP) is a rare papulosquamous disorder. Treatment is challenging; the armamentarium consists of topical corticosteroids, phototherapy, classic systemic treatments such as retinoids or immunosuppressive drugs, and most recently biologicals. However, the relative effectiveness of therapies is unclear. Our objective was to review the published literature on systemic treatment of PRP. A systematic review was conducted on PubMed and the Cochrane Library up to 5 September 2017. Studies evaluating any systemic treatments of PRP (except for historical treatments) were included. Overall, 182 studies met the predefined inclusion criteria, and reported on 475 patients and 652 courses of treatment. 42.0 % (225/514) of all patients treated with retinoids achieved an excellent response (isotretinoin: 61.1 % [102/167], etretinate: 47 % [54/115], and acitretin: 24.7 % [43/174]) compared to an excellent response rate of 33.1 % (53/160) with methotrexate. Therapy with biologicals was successful in 51.0 % of patients (71/133) (ustekinumab: 62.5 % [10/16], infliximab: 57.1 % [28/49], etanercept: 53.3 % [16/30], and adalimumab: 46.4 % [13/28]). This review balances effectiveness, side effects, experience, and drug costs in order to suggest a treatment regimen starting with isotretinoin as first-line, methotrexate as second-line and biologicals as third-line treatment for this difficult-to-treat dermatosis.

Clinical and Genetic Heterogeneity of CARD14 Mutations in Psoriatic Skin Disease

The CARD: BCL10: MALT1 (CBM) complex is an essential signaling node for maintaining both innate and adaptive immune responses. CBM complex components have gained considerable interest due to the dramatic effects of associated mutations in causing severe lymphomas, immunodeficiencies, carcinomas and inflammatory disease. While MALT1 and BCL10 are ubiquitous proteins, the CARD-containing proteins differ in their tissue expression. CARD14 is primarily expressed in keratinocytes. The CARD14-BCL10-MALT1 complex is activated by upstream pathogen-associated molecular pattern-recognition in vitro, highlighting a potentially crucial role in innate immune defense at the epidermal barrier. Recent findings have demonstrated how CARD14 orchestrates activation of the NF-κB and MAPK signaling pathways via recruitment of BCL10 and MALT1, leading to the upregulation of pro-inflammatory genes encoding IL-36γ, IL-8, Ccl20 and anti-microbial peptides. Following the identification of CARD14 gain-of function mutations as responsible for the psoriasis susceptibility locus PSORS2, the past years have witnessed a large volume of case reports and association studies describing CARD14 variants as causal or predisposing to a wide range of inflammatory skin disorders. Recent publications of mouse models also helped to better understand the physiological contribution of CARD14 to psoriasis pathogenesis. In this review, we summarize the clinical, genetic and functional aspects of human and murine CARD14 mutations and their contribution to psoriatic disease pathogenesis.

A Review on Pityriasis Rubra Pilaris

Pityriasis rubra pilaris (PRP) is an idiopathic, papulosquamous inflammatory dermatosis. It is characterized by hyperkeratotic follicular papules coalescing into orange-red scaly plaques, islands of sparing, and palmoplantar keratoderma. PRP can be subdivided into six clinical subtypes according to Griffiths' classification, based on age of onset, disease extent, prognosis, and other associated features. The sixth subtype of PRP occurs in individuals affected by HIV infection, and retroviral screening in all de novo cases of PRP is advised. Other reported associations include various infections, autoimmunity, drugs, and malignancies, although the true significance of these is still unclear. The genetic basis for familial cases, most commonly categorized under the fifth subtype, has been mapped to gain of function mutations in the caspase recruitment domain family, member 14 (CARD14) gene. Treatment of PRP remains a challenge to this day due to a paucity of high-quality evidence. Therapeutic regimens have been guided mostly by case reports and case series, with the mainstay of treatment being oral retinoids. Recently, biologics have emerged as a promising treatment for PRP. We present a review of the clinicopathologic features, pathogenesis, associated disorders, and treatment of PRP, with an emphasis and critical appraisal of the existing literature on the latter.

Management of refractory pityriasis rubra pilaris: challenges and solutions

Pityriasis rubra pilaris (PRP) is a rare chronic inflammatory papulosquamous skin disease. Its clinical presentation and evolution is very variable. The most frequent clinical features are follicular papules, progressing to yellow-orange erythroderma with round small areas of normal skin and the well-demarcated palmoplantar keratoderma. Actually, six different types of PRP have been described based on clinical characteristics, age of onset, and prognosis. The pathogenesis is still unknown, and treatment can be challenging. Available treatments are mainly based on case reports or case series of clinical experience because no controlled randomized trials have never been performed because of the rarity of the condition. Traditional systemic treatment consists in retinoids, which are actually considered as first-line therapy, but refractory cases that do not respond or relapse after drug interruption do exist. In recent years, numerous reports have demonstrated the efficacy of new agents such as biological drugs. This article is an overview on available therapeutic options, in particular for refractory forms of PRP.

Paraneoplastic pityriasis rubra pilaris: case report and literature review

Pityriasis rubra pilaris (PRP; MIM 173200) is an uncommon papulosquamous inflammatory dermatosis. Only a few cases of PRP associated with an underlying malignancy have been documented. We investigated a 59-year-old patient presenting with a fulminant form of PRP recalcitrant to systemic retinoid therapy, in whom the skin disease heralded a diagnosis of cholangiocarcinoma. We searched the MEDLINE database to find articles reporting on similar associations of PRP with malignancies. We identified 10 studies linking PRP and malignancies, but an association between PRP and cholangiocarcinoma has not yet been reported.

Dermatological Manifestations of Down's Syndrome

Background:

Down's syndrome (DS) is an extensively researched congenital condition characterized by mental retardation and distinct physical features. The cutaneous manifestations of DS are numerous, yet they seldom receive appropriate attention.

Objective:

To review the dermatological conditions associated with DS.

Methods:

A review of the medical literature.

Results:

DS is associated with an increased incidence of numerous dermatological conditions, some of which may be related to an immunological deficiency.

Conclusion:

Along with the importance of understanding the physical and psychosocial aspects of DS, an appreciation of the dermatological manifestations of this condition is integral to comprehensive medical care.

Severe, Disfiguring, Pityriasis Rubra Pilaris in a Woman in the Dominican Republic: Histopathologic Diagnosis and Response to Antiretroviral Therapy

Pityriasis rubra pilaris (PRP) is a poorly understood dermatologic condition usually accompanied by keratoderma and intense erythroderma with islands of unaffected skin. The PRP categories include HIV-associated PRP VI. A 23-year-old HIV-infected, dark-skinned woman in the Dominican Republic developed an extremely severe, disfiguring process characterized first by a dry scaly rash involving her face, trunk, and extremities with hyperpigmentation and islands of spared skin and minimal erythroderma, followed by alopecia and development of a thick horny layer on the scalp and face. The condition, histologically proven to be PRP, was accompanied by fever, wasting, and decline in CD4 count. Initiation of combination antiretroviral therapy (cART) was followed by rapid and sustained resolution of PRP. Nine years after ART initiation, she remains well, with viral suppression and immune recovery, without PRP recurrence but with sparse hair regrowth and facial scarring. In some dark-skinned patients, severe PRP may not feature characteristic erythroderma but will respond to combination ART.

Pityriasis Rubra Pilar and hypothyroidism

Pityriasis Rubra Pilaris (PRP) is a chronic and rare papulosquamous disorder. Treatment of Pityriasis Rubra Pilaris is based on empiric evidence because of several doubts regarding its etiology and also because of its relative rarity, making randomized studies difficult to perform. Some factors suggest that the metabolism of vitamin A is involved in pathogenesis. We report a case of Pityriasis Rubra Pilaris associated with autoimmune hypothyroidism which presented rapid and complete response after thyroid hormone replacement, without any association with other systemic treatment. In literature there are only three other reports of significant improvement of the lesions after hormonal correction. Deficiency of thyroid hormone inhibits the conversion of carotene into vitamin A, which would be responsible for the occurrence of Pityriasis Rubra Pilaris in this patient.

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.

Pityriasis rubra pilaris with the concomitant Leser — Trelat syndrome

The authors describe a rare case of pityriasis rubra pilaris with the concomitant Leser — Trelat syndrome. Taking into consideration contra-indications for UV therapy, Neotigason (acitretin) was prescribed in the dose of 25 mg a day. Nearly absolute regression of eruptions characteristic of pityriasis rubra pilaris and multiple seborrheic keratomas was observed.

Long-term ustekinumab treatment for refractory type I pityriasis rubra pilaris

BACKGROUND

Pityriasis rubra pilaris is a rare, chronic erythematous squamous disorder of unknown etiology. The disease is characterized initially by small follicular papules that coalesce into yellowish pink scaly plaques, palmoplantar keratoderma, diffuse furfuraceous scale of the scalp, and frequent progression to exfoliative erythroderma. Generally it is difficult to discern pityriasis rubra pilaris from other skin conditions but key-clinical features help in the diagnosis such as "islands" of spared skin within generalized erythroderma, follicular keratotic plugs, and an orange hue of the involved skin. Treatment options include topical vitamin D analogues, keratolytics, systemic acitretin, methotrexate, cyclosporine, azathioprine, fumaric acid esters, phototherapy, and anti-TNFα agents. Cases, of pityriasis rubra pilaris, successfully treated with a short-course ustekinumab therapy, have been reported.

MAIN OBSERVATIONS

We report a 31-year-old man with pityriasis rubra pilaris, refractory to conventional treatments, successfully treated with ustekinumab monotherapy for over 64 weeks. After failing conventional systemic agents (cyclosporine, aciretin and methotrexate), ustekinumab 45 mg has been prescribed, with the same dosing regimen as in psoriasis. The patient improved dramatically within 4 weeks of the first injection, with markedly less erythema and pruritus. Long-term control of the disease of the disease was achieved (64 weeks of treatment).

CONCLUSION

We report this case in order to show the striking and rapid efficacy of ustekinumab in reducing the signs and symptoms of the disease. Complete remission was achieved after the third injection, but also a long-term control of the disease. The therapy was well-tolerated in our patient and no adverse events occurred.

Familial pityriasis rubra pilaris is caused by mutations in CARD14

Pityriasis rubra pilaris (PRP) is a papulosquamous disorder phenotypically related to psoriasis. The disease has been occasionally shown to be inherited in an autosomal-dominant fashion. To identify the genetic cause of familial PRP, we ascertained four unrelated families affected by autosomal-dominant PRP. We initially mapped PRP to 17q25.3, a region overlapping with psoriasis susceptibility locus 2 (PSORS2 [MIM 602723]). Using a combination of linkage analysis followed by targeted whole-exome sequencing and candidate-gene screening, we identified three different heterozygous mutations in CARD14, which encodes caspase recruitment domain family, member 14. CARD14 was found to be specifically expressed in the skin. CARD14 is a known activator of nuclear factor kappa B signaling, which has been implicated in inflammatory disorders. Accordingly, CARD14 levels were increased, and p65 was found to be activated in the skin of PRP-affected individuals. The present data demonstrate that autosomal-dominant PRP is allelic to familial psoriasis, which was recently shown to also be caused by mutations in CARD14.

Virus-associated Trichodysplasia spinulosa

This review discusses the evolution of an emerging dermatologic entity, virus-associated trichodysplasia spinulosa (TS), and its association with the novel human TS polyomavirus. We will describe how this distinct dermatologic diagnosis has arisen from the convergence of strikingly similar histopathologic findings observed across several case reports. The case of virus-associated TS exemplifies how a combination of astute clinicopathologic observation and a well-designed molecular genetic approach can provide insights into the pathogenesis of cutaneous disease.

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.

Pityriasis rubra pilaris in a HIV-positive patient (Type 6 PRP)

A 45-year-old previously healthy man presented with minimally itchy spiny papular lesions of 3 years' duration and discharging nodular cystic lesions for the past 2 years. Initially, lesions appeared on his ears, followed by the gradual appearance of similar lesions over his face, back, and extremities. The lesions were not associated with photosensitivity. Over the years, the patient continued to have similar lesions without any significant response to various topical medications and oral antibiotics. There was no history of fever or any other systemic complaints and the patient denied any other significant medical problems in the past. Cutaneous examination revealed multiple, grouped, spiny papular lesions coalescing to form plaques at places over the ears, extremities, and trunk (Figure 1). Elongated, horny, follicular spires were noted on the top of the papular lesions. Multiple discharging nodular lesions with crusting were seen predominantly over the chest, abdomen, and back (Figure 2), and closed comedonal lesions were noted on the face and trunk. Multiple orange-brown scaly plaques were seen over the extensor aspect of the patient's thighs (Figure 1, inset). A few nails showed wedge-shaped thickening without subungual hyperkeratosis or other nail changes. Palms, soles, and oral mucosa were normal. Considering the atypical cutaneous findings, the clinical possibility of pityriasis rubra pilaris (human immunodeficiency virus [HIV]-associated type 6 PRP) was considered. Hematoxylin and eosin stain of skin biopsy specimens taken from the spiny papular and plaque lesions revealed marked hyperkeratosis with alternating orthokeratosis and parakeratosis with follicular keratotic plugging (Figure 3; Figure 3, inset). Irregular broad acanthosis was also detected in the epidermis. Dermis showed moderate perivascular lymphomononuclear inflammatory infiltrate. Thus, the skin biopsy was consistent with PRP. HIV serology by enzyme-linked immunosorbent assay (ELISA) with 3 different kits was found to be positive for HIV-1. The patient denied any risk factors associated with acquiring HIV infection, and laboratory values for complete blood cell count, routine serum biochemical profile, and lipid profile were normal. The patient was prescribed oral isotretinoin and asked to come for follow-up for CD4 T-cell count, but did not return.