Saturday, January 18, 2020

[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.

Wednesday, January 15, 2020

[考生加油] Dermatological Recall: Chapter 30 Pityriasis Lichenoides

從2020/01/11之後,煜彬就想趕快把下半段完成,以免被以為選舉完心情不好。

Chapter 30 :: Pityriasis Lichenoides(苔蘚樣糠疹)

:: Stefan M. Schieke & Gary S. Wood
鄭煜彬(20200114)
PITYRIASIS LICHENOIDES(PL)
PITYRIASIS LICHENOIDES(PL)

EPIDEMIOLOGY

What age group has higher prevalence rate of PL?
Children & young adults
Which season has higher prevalence of PL?
Fall and winter.
How much is the male-to-female ratio of PL?
1.5~3: 1(M>F)
Which one is more common, PLC or PLEVA?
PLC, which is 3 to 6 times more common than PLEVA.
CLINICAL FEATURES

What is the divide of PLC & PLEVA?
No, they are in a spectrum, and usually coexist.
What is the symptoms of PL?
Asymptomatic> pruritic or burning
What is the features of PLC?
Recurrent crops of erythematous scaly papules, regressing over several weeks to months
What is the features of PLEVA?
Recurrent crops of erythematous papules with crusts, vesicles, pustules, erosions, or ulcers before regressing in weeks (shorter than PLC)
What feature determine the duration of PL in children?
Distribution(not the number of lesions)
What distribution of PL has longer duration?
Peripheral (distal extremities) > central (trunk) > diffuse
What is the “clinical pattern” of PLC & PLEVA individually?
PLC: papulosquamous lesions (scaly papules)
PLEVA: papulonecrotic lesions (papules with ulcer)
What is PLEVA with severe ulceration & fever?
Pityriasis lichenoides with ulceronecrosis & hyperthermia (PLUH) or febrile ulceronecrotic Mucha–Habermann disease (FUMHD)
What is the features of PLUH?
Fever, purpuric papulonodules with central ulcers up to several cms (larger than PLEVA/PLC)
What is the common locations of PL?
Trunk & proximal extremities (all skin/mucous membranes is possible, regional/segmental lesions also exists)
What is the common skin sequelae of PL?
Postinflammatory hypo/hyper-pigmentation
What disease does the remnant of PLC look like? 
Idiopathic guttate hypomelanosis (PLC left postinflammatory hypopigmentation actually)
What disease does the remnant of PLEVA look like? 
Smallpox-like scar
What is the difference between smallpox & PLEVA? 
Smallpox: all lesions are in the same stage
PLEVA: in various stages of evolution
COMPLICATIONS

What is the most common complication of PL?
Secondary infection
What is the complications of PLEVA?
Low-grade fever, malaise, headache, and arthralgia (like a mild flu)
What is the complicatiolns of PLUH or FUMHD?
High fever, malaise, myalgia, arthralgia, gastrointestinal, & CNS symptoms(like a severe flu, can be fatal)
What is the relationship of PL & lymphoma?
Almost no relationship. (Only very rare cases progress to MF)
ETIOLOGY

What could cause PL?
Unknown, can be infections(toxoplasma gondii & virus), estrogen-progesterone therapy, chemotherapy, radiocontrast iodide, influenza vaccine, & HMG-CoA reductase inhibitors.
What is the Immunohistologic difference between PLC & PLEVA?
PLEVA: CD8+ T cells with TIA-1 & granzyme B(cytotoxic) predominate
PLC: CD4+ T (helper) predominate, CD8+ T, FoxP3+ T (regulatory)
What is the difference of clonality between PLC & PLEVA?
PLEVA: half cases have clonality
PLC: minority has clonality
What is the possible pathogenesis of PL?
Clonal cytotoxic memory T-cell lymphoproliferative
response to one or more foreign antigens.
Which disease has most overlapping features with PL?
Lymphomatoid papulosis (LyP)
What is the difference between PL & LyP?
l   LyP (type A & C): large CD30+ atypical lymphoid cells.
l   LyP has CD4+ cells which lack 1 or more mature T-cell antigens(CD2, 3, & 5)
DIAGNOSIS

How to diagnose PL?
Clinical & pathological features. Blood test may show leukocytosis &CD4/CD8, but of little value.
PATHOLOGY

What are the common pathological features of PL?
An interface dermatitis of lymphocytes (denser & more wedge shaped in acute lesions), exocytosis, parakeratosis, & RBC extravasation.
What features may appear in acute variants of PL?  
1.      Necrotic keratinocytes/vesicles/pustules/ ulcers.
2.      Lymphocytic vasculitis + fibrinoid degeneration
What is the meaning of CD30+ variant of PLEVA?
PL serve as fertile soil for the development of the CD30+ T-cell clone characteristic of lymphomatoid papulosis/ anaplastic large cell lymphoma
DIFFERENTIAL DIAGNOSIS

What is the differential diagnoses of PL and the method to distinguish them?
l   Secondary syphilis & virus exanthemas (serology)
l   LyP(CD30+ large atypical lymphoid cells)
l   Macular/papular variants of MF(small epidermotropic  atypical lymphoid cells with convoluted nuclei & a band-like superficial dermal lymphoid infiltrate)
MANAGEMENT

When should PL be treated?
The more acute course(PLEVA) & severe lesions (PLUH)
Mild, chronic lesions can be ignored.
How to treat PL?
l   Topical steroids & photo/photodynamic therapy
l   Systemic (antiinflammatory) antibiotics: tetracyclines, erythromycin, & azithromycin
l   Systemic steroids, low-dose methotrexate, calcineurin inhibitors(tacrolimus) & retinoids(bexarotene)
l   Bromelain (a pineapple extract, very effective)
l   Antibiotics for Gram(+) pathogens in secondary infections of PL lesions