31: Pityriasis Rosea Flashcards
What is the typical duration of a pityriasis rosea eruption?
The typical duration of a pityriasis rosea eruption is approximately 5 to 8 weeks. However, in the pediatric population, the average overall duration tends to be shorter, lasting approximately 16 days.
What are the common clinical features of pityriasis rosea?
Common clinical features of pityriasis rosea include:
- Herald patch: A solitary lesion on the trunk or extremity, typically well-demarcated, thin, oval to round, and pink.
- Secondary eruption: Smaller lesions appear on the trunk and proximal extremities, usually following the herald patch.
- Pruritus: Severe in 25% of patients, mild to moderate in 50%, and absent in 25%.
- Prodromal symptoms: May include malaise, nausea, headache, and gastrointestinal symptoms in 5% to 69% of cases.
What is the incidence of pityriasis rosea in the United States?
The incidence of pityriasis rosea in the United States is approximately 0.16%, which translates to about 160 cases per 100,000 person-years.
What are the atypical variants of pityriasis rosea?
Atypical variants of pityriasis rosea include:
- Localized PR: Limited to one truncal site.
- Unilateral PR: Does not cross the midline.
- Inverse PR: More common in children; involves body folds, face, and often distal extremities.
What is the significance of the herald patch in pityriasis rosea?
The herald patch is significant as it is often the first lesion to appear in pityriasis rosea, typically occurring on the trunk or extremities. It is well-demarcated, pink, and may be present in approximately 80% of cases. The herald patch is followed by a secondary eruption of smaller lesions.
A 25-year-old patient presents with a solitary, well-demarcated, oval plaque on the trunk. Two weeks later, smaller lesions appear on the trunk and proximal extremities. What is the likely diagnosis, and what is the initial lesion called?
The likely diagnosis is Pityriasis Rosea (PR). The initial lesion is called a herald patch.
A child presents with a herald patch and a secondary eruption within 4 days. How does this presentation differ from adults with Pityriasis Rosea?
In children, the time between the herald patch and secondary eruption is shorter (4 days) compared to the typical 2-week interval in adults.
A patient presents with a rash aligned along the lines of cleavage in a ‘Christmas tree’ distribution. What is the most likely diagnosis?
The most likely diagnosis is Pityriasis Rosea, as the rash typically aligns along the lines of cleavage in a ‘Christmas tree’ distribution.
A patient presents with a herald patch and secondary lesions that are eczematous and vesicular. What variant of Pityriasis Rosea might this represent?
This presentation might represent an atypical variant of Pityriasis Rosea, which can include eczematous and vesicular secondary lesions.
A patient presents with a herald patch and a secondary eruption limited to one truncal site. What variant of Pityriasis Rosea is this?
This is the localized variant of Pityriasis Rosea, where the eruption is limited to one truncal site.
A patient with Pityriasis Rosea is concerned about recurrence. What is the likelihood of relapse?
Relapse is rare, occurring in 1.8% to 3.7% of cases.
A patient with Pityriasis Rosea has a rash that includes oral ulcerative lesions. What is the significance of this finding?
Oral ulcerative lesions are more common in the persistent form of Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes lesions on the face and distal extremities. What variant of Pityriasis Rosea might this represent?
This presentation might represent the inverse variant of Pityriasis Rosea, which involves the face and distal extremities.
A patient with Pityriasis Rosea has a rash that includes lesions in a blaschkoid distribution. What is the significance of this finding?
A blaschkoid distribution is an atypical variant of Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes prominent acral involvement. What is the significance of this finding?
Prominent acral involvement is an atypical variant of Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes lesions on the dorsal feet. What is the significance of this finding?
Lesions on the dorsal feet are an atypical location for Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes lesions on the genitalia. What is the significance of this finding?
Lesions on the genitalia are an atypical location for Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes lesions on the scalp. What is the significance of this finding?
Lesions on the scalp are an atypical location for Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes lesions on the face. What is the significance of this finding?
Lesions on the face are an atypical location for Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes lesions on the neck. What is the significance of this finding?
Lesions on the neck are an atypical location for Pityriasis Rosea.
A patient with Pityriasis Rosea has a rash that includes lesions on the trunk and proximal extremities. What is the typical distribution of these lesions?
The lesions are typically bilaterally and symmetrically distributed on the trunk and proximal extremities.
A patient with Pityriasis Rosea has a rash that includes lesions on the distal extremities. What is the significance of this finding?
Lesions on the distal extremities are less common and may represent an atypical presentation of Pityriasis Rosea.
What is the typical duration of a pityriasis rosea eruption in adults compared to children, and what are the implications for diagnosis?
In adults, pityriasis rosea typically lasts for about 2 weeks before the onset of secondary lesions, while in children, this duration is shorter, averaging only 4 days. This difference in duration can impact the timing of diagnosis and treatment, as well as the recognition of prodromal symptoms that may precede the eruption.
How does the presentation of pityriasis rosea differ in pediatric patients compared to adults, particularly regarding the herald patch and secondary eruption?
In pediatric patients, the herald patch may present similarly but the time between its appearance and the secondary eruption is shorter, often lasting only 4 days. Additionally, the overall duration of the eruption tends to be shorter, averaging approximately 16 days, which may affect clinical management and patient reassurance.
What are the common cutaneous findings associated with pityriasis rosea, and how do they typically evolve over time?
The classic cutaneous finding is a herald patch, which is a well-demarcated, thin, oval to round pink plaque that may have a slightly depressed center and a fine collarette of scale. This herald patch typically enlarges over several days and is followed by a secondary eruption of smaller lesions that appear on the trunk and proximal extremities, often exhibiting a ‘Christmas tree’ distribution on the upper chest and back.
What are the potential prodromal symptoms that may precede the eruption of pityriasis rosea, and how frequently do they occur?
Prodromal symptoms such as malaise, nausea, headache, gastrointestinal issues, and upper respiratory symptoms may precede the eruption in 5% to 69% of patients. Recognizing these symptoms can be crucial for early diagnosis and management of pityriasis rosea.
What are the different variants of pityriasis rosea, and how do they differ in terms of presentation and recurrence?
Variants of pityriasis rosea include:
- Relapsing form: Involves a single episode of relapse within 1 year of the initial episode, which may be multiple relapses. Secondary episodes lack a herald patch, are shorter-lived, and consist of fewer and more localized lesions than the initial eruption.
- Persistent form: Characterized by eruptions lasting for more than 12 weeks without interruption, often with a herald patch and more common oral manifestations.
These variants can influence the clinical approach and patient management.
What are the potential complications of Pityriasis Rosea (PR) during pregnancy?
Pityriasis Rosea (PR) in pregnancy may be associated with adverse outcomes, including:
- 13% of women experiencing a miscarriage.
- In a study of 33 women who bore children, 27% had a premature delivery.
- No birth defects were noted, but hypotonia, weak motility, and hyporeactivity were observed in 18% of cases.
What are the essential diagnostic criteria for Pityriasis Rosea?
The essential diagnostic criteria for Pityriasis Rosea include:
- Discrete circular or oval lesions
- Scaling on most lesions
- Peripheral collarette of scale with central clearance on at least 2 lesions
Additionally, at least 1 of the following optional features should be present:
- Truncal and proximal limb distribution with less than 10% of lesions distal to the mid-upper arm and mid-thighs.
- Distribution of most lesions along the ribs.
- Herald patch appearing at least 2 days before the eruption.
What role does cell-mediated immunity play in the pathogenesis of Pityriasis Rosea?
Cell-mediated immunity is important in the pathogenesis of Pityriasis Rosea, characterized by:
- Predominantly T cells with an increased CD4-to-CD8 ratio.
- Increased proportion of Langerhans cells.
- Elevated levels of interleukin-17, interferon-γ, and vascular endothelial growth.
However, the overall pathogenesis of PR is poorly understood, and autoimmune mechanisms have been investigated without compelling evidence.
A pregnant woman develops Pityriasis Rosea (PR) at 14 weeks of gestation. What are the potential risks to her pregnancy?
PR in pregnancy may be associated with adverse outcomes, including a 13% miscarriage rate. If PR begins before 15 weeks of gestation, there is a 62% chance of abortion.
A patient with suspected Pityriasis Rosea has a rash that includes multiple small vesicles at the center of lesions. What diagnosis should be excluded?
The presence of multiple small vesicles at the center of lesions excludes the diagnosis of Pityriasis Rosea.
What are the potential complications of Pityriasis Rosea (PR) during pregnancy and their implications?
Pityriasis Rosea (PR) in pregnancy may be associated with adverse outcomes, including:
- Miscarriage: 13% of cases had a miscarriage.
- Premature Delivery: 27% of women in a study had a premature delivery.
- Infant Health: No birth defects were noted, but some infants exhibited hypotonia, weak motility, and hyporeactivity in 18% of cases.
What are the essential and optional diagnostic criteria for Pityriasis Rosea?
The diagnostic criteria for Pityriasis Rosea include:
Essential Features (3 required):
1. Discrete circular or oval lesions.
2. Scaling on most lesions.
3. Peripheral collarette of scale with central clearance on at least 2 lesions.
Optional Features (at least 1 required):
1. Truncal and proximal limb distribution with less than 10% of lesions distal to the mid-upper arm and mid-thighs.
2. Distribution of most lesions along the ribs.
3. Herald patch appearing at least 2 days before the eruption.
Exclusion Features (3 required):
1. Multiple small vesicles at the center of 2 or more lesions.
2. Most lesions on palmar or plantar skin surfaces.
3. Clinical or serological evidence of secondary syphilis.
How does the presence of HHV-7 relate to the pathogenesis of Pityriasis Rosea?
The presence of HHV-7 is thought to play a significant role in the pathogenesis of Pityriasis Rosea (PR) due to:
- Infectious Agent: PR has long been considered to be caused by an infectious agent, with HHV-7 DNA and messenger RNA found in both lesional and nonlesional PR skin.
- Reactivation: HHV-7 may influence and even cause reactivation of latent HHV-6, contributing to the disease process.
- Immune Response: The pathogenesis is poorly understood, but cell-mediated immunity, particularly T cells with a higher CD4-to-CD8 ratio, is important in the response to the infection.
What laboratory tests are typically performed for Pityriasis Rosea and what do they indicate?
- Routine blood tests: Normal results are expected.
- Leukocytosis: May be present.
- Erythrocyte sedimentation rate: Often elevated.
- Blood tests: Generally nonspecific; not needed or recommended for diagnosis.
What are the key pathological findings in Pityriasis Rosea?
-
Epidermal changes:
- Parakeratosis (focal, multifocal, or confluent)
- Orthokeratosis
- Mild acanthosis
- Thinned granular layer
- Spongiosis
- Lymphocyte exocytosis
-
Dermal findings:
- Superficial perivascular lymphocytic infiltrate
- Variable extravasated red blood cells
- Inflammatory infiltrate: Predominantly lymphocytes, with fewer neutrophils, histiocytes, and eosinophils.
What are the differential diagnoses for Pityriasis Rosea?
Condition | Key Features |
|—————————|——————————————————————————|
| Nummular eczema | More round lesions, does not follow lines of cleavage, affects extensor areas |
| Seborrheic dermatitis | Truncal lesions similar to PR, lesions on scalp/face |
| Guttate psoriasis | Does not follow lines of cleavage, lacks herald patch |
| Pityriasis lichenoides | More chronic and relapsing, lacks herald patch, involves extremities |
| Lichen planus | More pruritic, lacks collarette of scale, more violaceous color |
| Dermatophyte infection | Potassium hydroxide examination may be needed to distinguish |
| Secondary syphilis | Rash can be identical, oral lesions, persistent lymphadenopathy |
What is the typical clinical course and prognosis of Pityriasis Rosea?
- Self-resolution: Average of 45 days (2 weeks to 5 months).
- Persistent PR: Lasts longer than 3 months.
What is the typical clinical course and prognosis of Pityriasis Rosea?
- Self-resolution: Average of 45 days (2 weeks to 5 months).
- Persistent PR: Lasts longer than 3 months.
- Sequelae: Post-inflammatory hyperpigmentation or hypopigmentation.
- Long-term outcomes: No significant long-term clinical outcomes; recurrence is uncommon.
What management options are available for Pityriasis Rosea?
- No treatment necessary: Self-limited condition.
- Counseling: Important for reassurance regarding the self-limited nature.
- Topical steroids and antihistamines: Safe and may help with pruritus.
- Erythromycin: May hasten clearance of PR.
- Acyclovir: High-dose may improve clearance and associated symptoms.
- Ultraviolet B phototherapy: Some benefit in clearance time and pruritus.
What differential diagnosis should be considered for a rash resembling Pityriasis Rosea with lesions on the palms and soles?
Secondary syphilis should be considered, as it can present with a similar rash involving the palms and soles. Serologic tests like rapid plasma regain are required for confirmation.
What treatment options can be considered for severe pruritus in a patient with Pityriasis Rosea?
Topical steroids and antihistamines can be used for pruritus. High-dose acyclovir (800 mg 5 times daily for 1 week) may also hasten resolution and improve symptoms.
What is the condition called if Pityriasis Rosea lesions do not resolve after 3 months, and what are the potential sequelae?
This condition is called persistent Pityriasis Rosea. The only sequelae are post-inflammatory hyperpigmentation or hypopigmentation, especially in individuals with darker skin.
What additional tests should be performed for a patient with Pityriasis Rosea who has persistent lymphadenopathy and oral lesions?
Serologic tests for secondary syphilis, such as rapid plasma regain, should be performed to rule out this condition.
What differential diagnosis should be considered for Pityriasis Rosea with more violaceous and pruritic lesions lacking a collarette of scale?
Lichen planus should be considered, as it presents with more violaceous, pruritic lesions and lacks a collarette of scale.
What differential diagnosis should be considered for Pityriasis Rosea with a rash that does not follow the lines of cleavage and has thicker, more confluent scales?
Guttate psoriasis should be considered, as it does not follow the lines of cleavage and has thicker, more confluent scales.
What could be the cause of marked hyperpigmentation after a rash resolves in a patient with Pityriasis Rosea?
The hyperpigmentation could be due to a drug-induced Pityriasis Rosea-like eruption, which often leaves more marked hyperpigmentation.
What is the likely cause if a Pityriasis Rosea rash transitions to a lichenoid morphology?
The likely cause is a drug-induced Pityriasis Rosea-like eruption, which can transition to a lichenoid morphology.
What differential diagnosis should be considered for Pityriasis Rosea with lesions on the scalp and face?
Seborrheic dermatitis should be considered, as it can present with truncal lesions similar to Pityriasis Rosea and corresponding lesions on the scalp and face.
What differential diagnosis should be considered for Pityriasis Rosea with lesions in various stages?
Pityriasis lichenoides should be considered, as it presents with lesions in various stages and lacks a herald patch.
What differential diagnosis should be considered for Pityriasis Rosea with lesions on the extensor extremities?
Nummular eczema should be considered, as it has a predilection for the extensor extremities and does not follow the lines of cleavage.
What differential diagnosis should be considered for Pityriasis Rosea with lesions on the palms and soles, along with flu-like symptoms?
Secondary syphilis should be considered, as it can present with a similar rash involving the palms and soles, along with flu-like symptoms.
What is the significance of lesions on the palms and soles in a patient with Pityriasis Rosea?
Lesions on the palms and soles are atypical for Pityriasis Rosea and may suggest a differential diagnosis like secondary syphilis.
What is the significance of lesions on the scalp and face in a patient with Pityriasis Rosea?
Lesions on the scalp and face are atypical for Pityriasis Rosea and may suggest a differential diagnosis like seborrheic dermatitis.
What is the significance of lesions on the dorsal feet in a patient with Pityriasis Rosea?
Lesions on the dorsal feet are atypical for Pityriasis Rosea and may suggest a differential diagnosis like tinea corporis.
What is the significance of lesions on the genitalia in a patient with Pityriasis Rosea?
Lesions on the genitalia are atypical for Pityriasis Rosea and may suggest a differential diagnosis like lichen planus.
What is the significance of lesions on the neck in a patient with Pityriasis Rosea?
Lesions on the neck are atypical for Pityriasis Rosea and may suggest a differential diagnosis like seborrheic dermatitis.
What are the key histological features that can help differentiate Pityriasis Rosea from other skin conditions?
Key histological features of Pityriasis Rosea include:
-
Epidermal Changes:
- Parakeratosis (focal, multifocal, or confluent)
- Orthokeratosis
- Mild acanthosis
- Thinned granular layer
- Spongiosis
- Lymphocyte exocytosis
-
Dermal Changes:
- Superficial perivascular lymphocytic infiltrate
- Variable extravasated red blood cells
-
Inflammatory Infiltrate:
- Predominantly lymphocytes, with fewer neutrophils, histiocytes, and eosinophils.
How does the clinical course of Pityriasis Rosea typically progress, and what are the expected outcomes?
The clinical course of Pityriasis Rosea typically progresses as follows:
- Duration: Self-resolves after an average of 45 days (ranging from 2 weeks to 5 months).
- Persistent PR: Defined as lasting longer than 3 months.
- Sequelae: Possible post-inflammatory hyperpigmentation or hypopigmentation, especially in darker skin.
- Long-term Outcomes: No significant long-term clinical outcomes; recurrence is uncommon and usually occurs only once without long-term health consequences.
What are the differential diagnoses to consider when evaluating a patient with suspected Pityriasis Rosea?
Condition | Key Features |
|—————————|——————————————————————————|
| Nummular Eczema | Round lesions, does not follow lines of cleavage, predilection for extensor extremities |
| Seborrheic Dermatitis | Truncal lesions similar to PR, corresponding lesions on scalp/face |
| Guttate Psoriasis | Does not follow lines of cleavage, lacks herald patch, thicker scale typical of psoriasis |
| Pityriasis Lichenoides | More chronic and relapsing, lacks herald patch, lesions in various stages |
| Lichen Planus | More pruritic and chronic, lacks collarette of scale, more violaceous color |
| Dermatophyte Infection | Potassium hydroxide examination may be necessary to distinguish from herald patch |
| Secondary Syphilis | Rash can be identical, oral lesions, persistent lymphadenopathy |
| Medication-induced PR | Various medications can cause PR-like eruptions, requiring history review
What management strategies are recommended for Pityriasis Rosea, particularly for symptomatic relief?
- No Treatment Necessary: The condition is self-limited.
- Counseling: Provide reassurance regarding the natural history of PR.
- Topical Steroids and Antihistamines: Safe and may help with associated pruritus.
- Erythromycin: May hasten the clearance of PR.
- Acyclovir: High-dose acyclovir (800 mg 5 times daily) may improve clearance and associated symptoms.
- Ultraviolet B Phototherapy: Some benefit in PR clearance time and pruritus.
PR is a common self-limited papulosquamous eruption
typically lasting _____, most common in _____ (between the ages of _____ years).
5 to 8 weeks
teenagers and young adults
10-35
PR begins with a solitary lesion on the trunk “herald
patch” which remains isolated on average for _____ in adults and _____ in children
2 weeks
4 days
Relapsing form of PR: single episode of relapse within _____ of the initial episode.
1 year
Persistent form of PR: eruption lasts for greater than _____ without interruption.
12 weeks
Pediatric form of PR: duration of eruption tends to be shorter (_____ days).
16
Vesicular lesions may be arranged in a rosette and are more common in _____.
children and young adults
Mucosal lesions have been reported in up to _____% of patients with PR.
16
Most common form of oral lesions in PR?
Ulcerations
Atypical variants of PR (unilateral, localized, inverse) make up approximately _____% of cases.
20
Inverse PR is more common in _____ and is characterized by the involvement of body folds, face, and often distal extremities.
children
Classic PR has a slightly _____ preponderance.
female
Etiologic agent of PR?
HHV7 > HHV6
Medications that can cause a PR-like reaction?
“COMBPLICATING”
PR typically self-resolves after an average of _____ (range: _____)
45 days
2 weeks to 5 months
___% of pregnant patients with PR have miscarriages.
13
Anxiety and depression is found in _____% of patients with PR.
30
If PR begins during a pregnancy of <15 weeks, there is a _____% chance of abortion. Of those who bear children, _____% had premature delivery, _____% had hypotonia, weak motility and hyporeactivity. There are no birth defects.
62
27
18
This antibacterial is reported to hasten the clearance of PR.
Erythromycin (macrolide)
How do you give acyclovir for PR to hasten clearance of lesions, improve pruritus and systemic symptoms?
High dose: 800 mg 5x/day for 7 days
DDx of PR:
- Most likely?
- To consider?
- Always rule out?
