29: Pityriasis Rubra Pilaris Flashcards
What are the typical clinical features of Type I (classic adult) pityriasis rubra pilaris?
Type I (classic adult) pityriasis rubra pilaris typically presents with:
- Erythematous macules forming patches
- Follicular hyperkeratotic papules on the upper half of the body
- Yellow-orange scaling dermatitis that may spread to generalized erythroderma over 2 to 3 months
- Sharply demarcated islands of unaffected skin (nappes claires)
- Waxy, diffuse, yellowish keratoderma of palms and soles
- Nail changes including thickening, splinter hemorrhages, and subungual hyperkeratosis.
What distinguishes Type IV (circumscribed juvenile) pityriasis rubra pilaris from other types?
Type IV (circumscribed juvenile) pityriasis rubra pilaris is characterized by:
- Well-demarcated hyperkeratotic erythematous plaques on the elbows and knees resembling localized psoriasis
- It does not progress to the more widespread classical type
- Palmoplantar keratoderma may be absent
- A 3-year remission rate of 32%.
What is the clinical course and characteristics of Type III (classic juvenile) pityriasis rubra pilaris?
Type III (classic juvenile) pityriasis rubra pilaris has the following characteristics:
- It is the clinical counterpart of Type I PRP in children
- Onset occurs between 5 to 10 years of age
- The clinical course is shorter, with clearing typically after 1 year.
What are the key features of Type V (atypical juvenile) pityriasis rubra pilaris?
Type V (atypical juvenile) pityriasis rubra pilaris is characterized by:
- Early age of onset
- Chronic course
- Most patients have a familial link with a gain-of-function mutation in the CARD14 gene
- Hyperkeratotic follicular lesions
- Some patients exhibit scleroderma-like features affecting hands and feet.
A patient with PRP develops ichthyosiform scaling, areas of follicular hyperkeratosis, and sparseness of scalp hair. What type of PRP is this, and what is its typical duration?
This is Type II (atypical adult) PRP, which typically has a long duration of more than 20 years.
A child aged 6 presents with PRP that resolves within one year. What type of PRP is this, and how does it differ from the adult counterpart?
This is Type III (classic juvenile) PRP. It is the clinical counterpart of Type I PRP in adults but has a shorter clinical course.
A child aged 7 presents with well-demarcated hyperkeratotic erythematous plaques on the elbows and knees resembling localized psoriasis. What type of PRP is this, and what is its characteristic feature?
This is Type IV (circumscribed juvenile) PRP. Its characteristic feature is palmoplantar keratoderma, although it may be absent.
A patient with PRP has a chronic course and scleroderma-like features affecting the hands and feet. Genetic testing reveals a gain-of-function mutation in the CARD14 gene. What type of PRP is this?
This is Type V (atypical juvenile) PRP, which is associated with familial cases and CARD14 mutations.
A patient with HIV presents with follicular papules, prominent follicular plugging, and symmetrically distributed lesions on extensor surfaces progressing to erythroderma. What type of PRP is this?
This is Type VI (HIV-associated) PRP.
A 35-year-old patient presents with erythematous macules forming patches and follicular hyperkeratotic papules on the upper half of their body. Over two months, this progresses to generalized erythroderma. What is the most likely diagnosis and its hallmark feature?
The most likely diagnosis is Type I (classic adult) Pityriasis Rubra Pilaris (PRP). The hallmark feature is sharply demarcated islands of unaffected skin, also known as ‘nappes claires.’
A patient with PRP presents with acne conglobata, hidradenitis suppurativa, and lichen spinulosus. What type of PRP is this, and what is its association?
This is Type VI (HIV-associated) PRP, often linked to HIV infection.
A patient with PRP has nail plate thickening, splinter hemorrhages, and subungual hyperkeratosis. What type of PRP is this, and what other features are associated with it?
This is Type I (classic adult) PRP. Other features include sharply demarcated islands of unaffected skin (‘nappes claires’) and waxy, diffuse, yellowish keratoderma of the palms and soles.
A patient with PRP has a chronic course and does not show spontaneous resolution. What type of PRP is this, and what genetic mutation is it associated with?
This is Type V (atypical juvenile) PRP, associated with gain-of-function mutations in the CARD14 gene.
What are the key clinical features of Type I (classic adult) Pityriasis Rubra Pilaris?
- Most common subtype, comprising >50% of cases.
- Begins with erythematous macules forming patches and follicular hyperkeratotic papules on the upper body.
- Characterized by yellow-orange scaling dermatitis that can progress to generalized erythroderma over 2 to 3 months.
- Diagnostic hallmark: sharply demarcated islands of unaffected skin, known as ‘nappes claires’.
- Associated with waxy, diffuse yellowish keratoderma of palms and soles, nail changes (thickening, splinter hemorrhages, subungual hyperkeratosis), and possible ectropion in uniform facial involvement.
How does Type IV (circumscribed juvenile) Pityriasis Rubra Pilaris differ from Type I?
- Type IV is characterized by well-demarcated hyperkeratotic erythematous plaques on the elbows and knees, resembling localized psoriasis.
- It occurs in prepubertal children and young adults, with a shorter clinical course compared to Type I.
- Type IV does not progress to the more widespread classical type seen in Type I.
- Palmoplantar keratoderma is characteristic but may be absent.
- The 3-year remission rate for Type IV is 32%.
What is the significance of CARD14 mutations in Pityriasis Rubra Pilaris?
- CARD14 mutations are linked to familial cases of Pityriasis Rubra Pilaris, particularly in Type V (atypical juvenile).
- These mutations are associated with early onset and a chronic course of the disease.
- Patients with these mutations may exhibit hyperkeratotic follicular lesions and some may develop scleroderma-like features affecting hands and feet.
What distinguishes Type II (atypical adult) Pityriasis Rubra Pilaris from other types?
- Type II is atypical in morphology and accounts for about 5% of cases.
- It has a long duration, often exceeding 20 years.
- The clinical presentation resembles ichthyosiform scaling, with areas of follicular hyperkeratosis and sparse scalp hair.
- Unlike Type I, there is no observed cephalocaudal progression, and patients have less tendency to develop erythroderma.
What are the clinical implications of the different types of Pityriasis Rubra Pilaris?
- Understanding the different types aids in diagnosis and management strategies.
- Type I requires monitoring for potential progression to erythroderma, while Type IV may have a more localized presentation.
- Familial cases linked to CARD14 mutations (Type V) may necessitate genetic counseling and tailored treatment approaches.
- Atypical presentations (Type II) may require long-term management strategies due to their chronic nature.
What are the clinical features of classic adult type Pityriasis Rubra Pilaris?
Classic adult type Pityriasis Rubra Pilaris presents with:
- Monomorphic regions of affected skin
- Sharp margins between affected and unaffected areas
- Diffuse alopecia (hair loss)
- Ectropion (outward turning of the eyelid)
What is the appearance of erythrodermic patients with classic adult type Pityriasis Rubra Pilaris?
Erythrodermic patients with classic adult type Pityriasis Rubra Pilaris typically exhibit:
- Psoriasiform scaling (similar to psoriasis)
- Islands of normal skin amidst the affected areas
What are the clinical features that differentiate classic adult type Pityriasis Rubra Pilaris from other skin conditions?
Classic adult type Pityriasis Rubra Pilaris is characterized by:
- Monomorphic regions of affected skin
- Sharp margins between affected and unaffected areas
- Diffuse alopecia (hair loss)
- Ectropion (outward turning of the eyelid)
How does erythrodermic Pityriasis Rubra Pilaris present clinically compared to classic adult type?
Erythrodermic Pityriasis Rubra Pilaris presents with:
- Psoriasiform scaling (similar to psoriasis)
- Islands of normal skin amidst the affected areas
- More extensive skin involvement compared to classic adult type, which may have more localized lesions.
What are the associations of Pityriasis Rubra Pilaris with HIV infections?
HIV infections may be the first sign of HIV infection, and clinical responses have been observed with antiretroviral therapy.
What is the significance of the CARD14 gene in Pityriasis Rubra Pilaris?
Type V PRP is linked to gain-of-function mutations in the CARD14 gene, which is expressed in the skin and encodes a protein that activates nuclear factor-κB signaling.
What are the histologic differences between Pityriasis Rubra Pilaris and Psoriasis?
Feature | Pityriasis Rubra Pilaris | Psoriasis |
|———|————————|———-|
| Hypergranulosis | Present | Absent |
| Thickening of rete ridges | Present | Elongation of rete ridges |
| Vascular dilation | Limited | Present |
| Neutrophilic infiltration | Absent | Present (Munro microabscesses) |
| Parakeratosis | Alternating horizontal and vertical | Present |
| Follicular hyperkeratosis | Present | Absent |
What are the clinical management options for Pityriasis Rubra Pilaris?
Management options include corticosteroids, salicylic acid in combination with oral retinoids, methotrexate, and tumor necrosis factor (TNF) inhibitors, which are considered most helpful from the patient’s point of view.
What is the prognosis for classic adult type I Pityriasis Rubra Pilaris?
Classic adult type I typically resolves within 3 years, with a recurrence rate of up to 20%.
A patient with PRP has a history of seborrheic dermatitis-like scalp manifestations. What is the significance of this finding?
Seborrheic dermatitis-like scalp manifestations can mimic the initial presentation of PRP, making it an important differential diagnosis.
A patient with PRP has a history of upper respiratory tract infection (URTI). What is the proposed pathogenic mechanism linking PRP to infections?
The proposed mechanism involves pathogenic activation of inflammatory pathways associated with infections such as URTI or HIV.
A patient with PRP has a history of malignancy. What is the significance of this association?
Malignancies are one of the associations of PRP, suggesting a possible link to systemic conditions.
What are the key histological differences between PRP and psoriasis?
Key differences include hypergranulosis in PRP versus hypogranulosis in psoriasis, thickening of the rete ridges in PRP versus elongation in psoriasis, limited vascular dilatation in PRP versus vascular dilation in psoriasis, and lack of neutrophilic infiltration in PRP versus intraepidermal Munro microabscesses in psoriasis.
A patient with PRP has a mutation in the CARD14 gene. What is the role of CARD14 in the pathogenesis of PRP?
CARD14 encodes the caspase recruitment domain family member 14, an activator of nuclear factor-κB signaling. Mutations lead to abnormal activation of inflammatory pathways, contributing to PRP.
A patient with PRP presents with alternating horizontal and vertical parakeratosis and orthokeratosis. What does this histological feature indicate?
This histological feature is indicative of PRP and helps differentiate it from psoriasis.
A patient with PRP has upregulated expression of proinflammatory cytokines such as TNF, IL-6, IL-12, IL-23, and IL-1β. What does this suggest about the disease’s classification?
This suggests that PRP is classified as a papulosquamous disease resulting from abnormal activation of inflammatory pathways.
A patient with PRP is diagnosed based on clinical features. What are the key diagnostic criteria?
Key diagnostic criteria include characteristic skin lesions and the age of onset. A biopsy may be performed to differentiate PRP from psoriasis.
A patient with PRP has a history of autoimmune disease. What is the significance of this association?
Autoimmune diseases are one of the associations of PRP, suggesting a possible link to immune dysregulation.
What are the key histologic differences between Pityriasis Rubra Pilaris (PRP) and psoriasis?
Feature | Pityriasis Rubra Pilaris (PRP) | Psoriasis |
|———|——————————-|———-|
| Hypergranulosis | Present | Absent |
| Rete Ridges | Thickening | Elongation |
| Vascular Dilation | Limited | Present |
| Neutrophilic Infiltration | Absent | Intraepidermal Munro microabscesses |
| Parakeratosis | Alternating horizontal and vertical | Present |
| Orthokeratosis | Present | Absent |
| Follicular Hyperkeratosis | Present | Absent |
What are the clinical implications of the associations of Pityriasis Rubra Pilaris with HIV infections?
- HIV infections may be the first sign of HIV infection.
- Clinical responses to Pityriasis Rubra Pilaris have been observed with antiretroviral therapy.
- It is important to consider HIV testing in patients presenting with PRP, especially if other risk factors are present.
What is parakeratosis?
Alternating horizontal and vertical
Present
What is orthokeratosis?
Present
Absent
What is follicular hyperkeratosis?
Present
Absent
What are the management options for Pityriasis Rubra Pilaris and their effectiveness?
- Corticosteroids: Effective in reducing inflammation.
- Salicylic Acid: Helps in scaling and skin turnover.
- Oral Retinoids: Useful for severe cases.
- Methotrexate: Can be effective in resistant cases.
- TNF Inhibitors: Most helpful from the patient’s perspective, especially in severe cases.
What is the prognosis for Classic adult type I PRP?
- Resolves within 3 years with a recurrence rate of up to 20%.
What is the prognosis for Classic juvenile type III PRP?
- Resolves within 1 to 2 years.
What is the prognosis for atypical variants of PRP?
- Atypical variants (types II and IV) have a less favorable prognosis for remission, with type V showing little to no tendency to resolve spontaneously.
What are the first-line systemic treatments for Pityriasis Rubra Pilaris?
The first-line systemic treatments include:
- Oral Retinoids: Acitretin and isotretinoin (1-2 mg/kg/day) are effective.
- Methotrexate: The second most used drug; teratogenic and can be combined with oral retinoids in severe cases.
- PUVA Therapy: Psoralen and ultraviolet A (PUVA) alone or in combination with oral retinoids.
What topical treatments are recommended for Pityriasis Rubra Pilaris?
Topical treatments include:
- Emollients: Used as a water-in-oil emulsion.
- Keratolytic Treatments: Such as salicylic acid, which is used where hyperkeratosis is the leading sign.
- Topical Corticosteroids: To dampen the local inflammatory response.
- Vitamin D3 Analogs: They inhibit cutaneous inflammation and promote normal keratinization, but treatment is restricted to no more than 30% of body surface.
What are the second-line systemic treatments for Pityriasis Rubra Pilaris?
Second-line systemic treatments include:
- Fumaric Acid Esters.
- Apremilast: A phosphodiesterase 4-inhibitor.
- Anti-TNF-α: Such as ustekinumab (anti-IL-12/IL-23p40) and anti-IL-17.
- Extracorporeal Photopheresis.
- Cyclosporine, Glucocorticosteroids, or Azathioprine: Evidence for effectiveness is low.
- Triple Antiretroviral Therapy: Particularly for PRP associated with HIV infection.
What is the purpose of topical calcineurin inhibitors in PRP treatment?
Topical calcineurin inhibitors are used to dampen the local inflammatory response in PRP.
For which types of PRP is ustekinumab effective?
Ustekinumab is effective for Type I PRP and PRP with CARD14 mutations (Type V) but not for Type IV PRP.
What is the mechanism of action of topical vitamin D3 analogs, and what is the limitation of this treatment?
Vitamin D3 analogs inhibit cutaneous inflammation and epidermal proliferation while enhancing normal keratinization. However, treatment is limited to no more than 30% of the body surface due to percutaneous resorption.
What are the potential risks of methotrexate in PRP treatment?
Methotrexate is teratogenic and is combined with oral retinoids in severe cases of PRP.
What precaution should be taken before initiating phototherapy for PRP?
Phototesting should be performed before initiating UV treatment, as PRP can be aggravated by UV light.
What is the rationale for using fumaric acid esters in PRP treatment?
Fumaric acid esters are used to modulate inflammatory pathways in PRP.
In what cases is extracorporeal photopheresis considered for PRP treatment?
Extracorporeal photopheresis is considered in refractory cases of PRP.
What are the risks associated with oral retinoids in PRP treatment?
The likely cause is the teratogenic effect of oral retinoids, such as acitretin or isotretinoin. Risks include hyperostosis and teratogenicity.
What systemic therapies could be considered for unresponsive PRP patients?
Systemic therapies include oral retinoids (first-line), methotrexate, phototherapy (PUVA, UVB), fumaric acid esters, apremilast, and biologics targeting TNF-α, IL-12/IL-23p40, or IL-17.
What therapy is effective for PRP associated with HIV infection?
The therapy is triple antiretroviral therapy, which is effective because it addresses the underlying HIV infection that may trigger PRP.
What are the key components of topical treatment for Pityriasis Rubra Pilaris?
- Emollients: Used for hydration (water-in-oil emulsion).
- Keratolytics: Such as salicylic acid, to reduce hyperkeratosis.
- Topical corticosteroids: To dampen local inflammatory response.
- Vitamin D3 analogs: Enhance normal keratinization and reduce inflammation, but limited to 30% of body surface.
What are the considerations for using biologics in the treatment of Pityriasis Rubra Pilaris?
- Biologics targeting TNF-α, IL-12/IL-23p40, and IL-17: Considered second-line treatment options.
- Ustekinumab: Effective for type I PRP and CARD14 mutation (type V), but not for type IV PRP.
- Monitoring for teratogenic effects: Important when using methotrexate and other systemic therapies.
What precautions should be taken when initiating UV treatment for Pityriasis Rubra Pilaris?
- Phototesting: Should be performed before starting UV treatment to assess skin response.
- Avoidance of UV light: PRP can be aggravated by UV light, necessitating careful monitoring during treatment.
