Pityriasis Lichenoides (PLEVA and PLC)

Question 1

What is the cause of Pit. Lichenoides?

Answer 1

Unknown

Postulated to be a response to foreign antigens such as infectious agents and drugs

Implicated infections
* VZV
* HIV
* EBV
* Parvovirus

Implicated drugs:
* estrogen
* progresterone
* TNF inhibitors
* Vaccines
* Radiocontrast dyes

Question 2

Who gets Pityriasis Lichenoides?

Answer 2

Children > Adults

Males > Females

Question 3

What does PLEVA stand for?

Answer 3

Pityriasis Lichenoides et varioliformis acuta

Question 4

How does PLEVA present?

Answer 4

Recurrent crops of spontaneously regressing **erythematous to purpuric papules **

Individual lesions develop crusts, ulcers, and occasionally vesicles or pustules

May heal with scars

Ususally assymptomatic, although can be pruritic

Often resolve within weeks.

Question 5

Describe these lesions?

Answer 5

Eerythematous to brown crusted papules

Areas of ulceration

Areas of hypopigmentation

Fine scale

Question 6

How does PLC present?

Answer 6

Recurrent crops of spontaneously regressing erythematous to purpuric papules

papules are erythematous to red–brown and scaly
Polymorphic
Regress over weeks to months
Often resolve as hypopigmented macules
Fine ‘mica like’ scale

Question 7

Describe the histopathology?

Answer 7

Parakeratosis
Perivascular lymphocytic infiltrates

Erythrocytes extravasation

Necrotic Keratinocytes

No atypical lymphocytes
No pautriers microabscesses

Question 8

What is the DDx of PLEVA?

Answer 8

○ Lymphomatoid papulosis
○ Cutaneous Small Vessel vasulitis
○ Varicella
○ Anthropod reaction
○ EM
○ Lichenoid drug eruption
○ Folliculitis
○ Dermatits Herpetiformis

Question 9

What is the DDx of PLC?

Answer 9

○ Small Plaque Parapsoriasis
○ Guttate Psoriasis
○ Lichen Planus
○ Pit. Rosea
○ Secondary Syphilis
○ Lymphomatoid papules
○ Papular dermatitis
○ Lichenoid Drug eruption

Question 10

How do you treat Pit. Lichenoides?

Answer 10

Limited evidence
* Rx guided by uncorntolled case series, case reports, anecdotes

First-line therapy:
* topical corticosteroids,
* tetracyclines,
* erythromycin,
* Phototherapy (nbUVB)

Second or third line
* dapsone
* oral reinoids
* antihistamines

** More fulminant cases:**
○ low-dose weekly methotrexate.
○ systemic corticosteroids,
○ IVIg
○ Cyclosporine
○ TNF inhibitors