[考生加油] Dermatological Recall: Chapter 31 Pityriasis Rosea 玫瑰糠疹

玫瑰糠疹雖然不算罕見，大小教科書也都一直會提到，但在臨床實戰上卻沒有那麼容易診斷，甚至需要動用到診斷要件。這種疾病儘管不會有嚴重併發症，卻會造成病人的恐慌，也一直是皮膚科醫師的重要課題。

Chapter 31 :: Pityriasis Rosea

:: Matthew Clark & Johann E. Gudjonsson

鄭煜彬(20200117)

What is the meaning of pityriasis rosea?	Pink (rosea) scales (pityriasis).
EPIDEMIOLOGY
When is PR found commonly?	In colder months, but not supported by all studies.
Why is PR thought as infectious disease?	PR usually has clustering of cases.
Which gender has higher prevalence?	Female(F:M=1.39: 1, especially pregnant women)
What age group has highest prevalence?	10-35 years(teenagers & young adults)
Does PR relapse?	Yes, but rare(only 1.8% to 3.7%).
CLINICAL FEATURES
HISTORY
What is the first lesion of classic PR?	The herald patch: a solitary lesion on the trunk or less commonly an extremity.
How long is the time between herald patch & secondary(2°) eruptions?	On average l   2 weeks in adults l   4 days in children
Where is the locations of the 2° eruptions of PR?	Trunk & proximal extremities
What is the prodromal symptoms before or with the 2° eruption?	Malaise, nausea, headache, gastrointestinal, & upper respiratory symptoms (flu-like), & lymphadenopathy.
What is the most common symptom of PR rashes?	Pruritus(severe: mild/moderate: absent= 1:2:1)
What is the variants in pediatric patients(< 10 y/o)?	Relapsing form: single (multiple is rare) episode of relapse within 1 year of the initial episode. Persistent form: last for > 12 weeks without Interruption
What is the features of relapsing PR?	Lack a herald patch, shorter lived, fewer, & more localized lesions.
What is the features of persistent PR?	Has a herald patch, more common oral manifestations
How long is the duration of pediatric PR?	on average 16 days (shorter than that on adults)
CUTANEOUS FINDINGS
What is the features of classic herald patch?	One/multiple well-demarcated, thin, oval to round, pink/rose/colored/erythematous/ hyperpigmented plaque with a slightly depressed center & fine collarette of scale in the periphery.
Where is the locations of herald patch?	Trunk (50%)>extremities>neck>> dorsal feet/face/ scalp/genitalia
How big is the size of herald patch?	>3 cm(2-10 cm
How much is the incidence of the herald patch?	80% (12% to 94%)
How much is the incidence of the multiple herald patch?	5%
How long is the time between the herald patch & 2° eruptions?	2 weeks (a few hours to 3 months), but sometimes no 2° eruptions.
What is the features of 2° eruption of PR?	Multiple, round-to-oval, 0.5- to 1.5-cm, light pink macules, papules, & plaques (smaller herald patch)
Where is the locations of 2° eruption?	Trunk & proximal extremities>> distal extremities >>palms & soles.
What is the specific distribution of 2° eruptions of PR?	“Christmas tree” distribution on the upper chest & back: long axis of the lesions parallel to lines of cleavage (ribs)
How about the course of 2° eruption?	Appears 2 weeks after herald patch, occurs in crops every few days, reaches its maximum 2 weeks later, then disappears in 45 days.
How about the relationship between PR & sun-exposure?	Some are confined to sun-protected skin; others are confined to sun-exposed skin. Most are randomly distributed.
What is the atypical forms of 2° eruption?	Eczematous, papular, follicular, vesicular, urticarial, pustular, & purpuric forms.
What is the configuration of vesicular lesions of PR?	They are arranged in a rosette.
What age group has higher incidence of vesicular lesions?	Children & young adults
How much is the incidence of mucosal lesions in PR cases?	16% (uncommon)
What is the clinical features of oral lesions of PR?	They can be punctate hemorrhagic, ulcerative, erythematous macules, plaques, bullous, & annular lesions. Ulcer is most common.
What is the atypical variants of PR? (hint: 5, distribution)	Unilateral(not cross midline), localized(1 truncal site), & inverse(children’s folds, face, distal limbs), blaschkoid, acral variants.
COMPLICATIONS
What is the complication of PR in the healthy individuals?	Anxiety & depression, no long-term complications
What is the complication of PR in the pregnants?	PR before 15 weeks: higher miscarriage PR after 15 weeks: higher premature delivery ± hypotonia, weak motility, & hyporeactivity
ETIOLOGY & PATHOGENESIS
What pathogens may induce pityriasis rosea?	HHV-7 and/or HHV-6
What is the relationship between PR & HHVs?	PR is the T cell infiltrate (cell-mediated immunity) caused by primary infection or reactivation of HHV-7 and/or HHV-6.
What is the changes of cells, cytokines, & proteins in PR?	⇧ (1) CD4-to-CD8 ratio & Langerhans cells (3) IL-17, IFN-γ (4)VEGF, interferon-inducible protein-10 (CXCL10).
DIAGNOSIS
What is the clinical diagnostic criteria of PR?	3 essential + at least 1 optional, no exclusion Essential features (圓環屑) l   Discrete circular or oval lesions l   Scaling on most lesions l   Peripheral collarette of scale with central clearance on ≥ 2 lesions. Optional features (軀近、肋、先) l   A truncal & proximal limb distribution, < 10% lesions distal to the middle of arms & thighs l   Distribution of most lesions along the ribs l   A herald patch ≥ 2 days before the eruption. 3 exclusion features l   Central, multiple small vesicles at ≥ 2 lesions l   Most lesions on palmar or plantar skin l   Clinical or serological evidence of 2° syphilis.
LABORATORY TESTING
When should you check lab in PR patients?	To rule out 2° syphilis
PATHOLOGY
What does PR look like in pathology?	Subacute eczema + extravasated RBC
What are the features of PR?	Epidermis: focal/multifocal/confluent parakeratosis, orthokeratosis, mild acanthosis; a thinned granular layer; & spongiosis+ lymphocyte exocytosis Dermis: a superficial perivascular lymphocytic infiltrate + extravasated RBC
What is the difference of pathology between herald patch & 2° eruption?	No difference. But herald patch has thicker acanthosis & deeper infiltration.
DIFFERENTIAL DIAGNOSIS
What diseases can be the differential diagnosis of PR?	Papulosquamous disorders: l   Nummular eczema (round, no X’mas tree) l   Guttate psoriasis(no X’mas tree, no herald patch) l   Lichen planus (pruritic, chronic, violet, more distal limbs, no collarette of scales) l   Pityriasis lichenoides (chronic, relapsing course, no herald patch, lesions in various stages, limbs) l   Tinea corporis(KOH) l   Parapsoriasis(no X’mas tree, no herald patch, chronic course) l   Seborrheic dermatitis(face & scalp), l   Secondary syphilis (oral/palmoplantar lesions, persistent LAP, serology+, split papules, moth-eaten alopecia, condyloma lata ).
What are the possible culprits of drug-induced PR?	Barbiturates, captopril, clonidine, gold, metronidazole, d-penicillamine, isotretinoin, levamisole, NSAID, omeprazole, terbinafine, imatinib, & adalimumab.
Why does adalimumab induce PR-like eruption?	Adalimumab dampens T-helper 1 cell response and predispose to viral infection or reactivation.
What is the difference between PR & drug-induced PR?	Drug-induced PR has more hyperpigmentation & lichenoid morphology. More interface dermatitis, dyskeratotic keratinocytes, & eosinophils in pathology.
CLINICAL COURSE AND PROGNOSIS
How long is the duration of PR?	Average: 45 days (range: 2 weeks to 5 months)
What is the definition of persistent PR?	Eruptions last > 3 months (12 weeks)
What is the cutaneous sequela of PR?	Post-inflammatory hyper/hypopigmentation
MANAGEMENT
What should you do to most cases of PR?	No treatment is necessary because it is self-limited
How to treat PR?	l   Topical: steroids & antihistamines (just improve pruritus) l   Oral: acyclovir (800 mg 5 time) >> macrolide (erythromycin & azithromycin) l   UVB
How to prevent PR?	No way.