Pityriasis rosea,lichenoides

PITYRIASIS ROSEA

PITYRIASIS LICHENOIDES BY AJAI SASIMALABAR MEDICAL COLLEGE

PITYRIASIS

• Any of several skin diseases marked by the formation and desquamation of fine scales

PITYRIASIS ROSEA

• Self limited dermatitis lasting from 4-7 weeks• Predominantly occur in adolscents and young

adults• May be asymptomatic or pruritic• Etiology unknown,viral origin has been

suggested

• Characterized by development of self limiting eruption

• Eruption preceded with large scaly annular plaque known as Herald patch or mother patch

• It is a raised Plaque• Within a week after heralad patch formation• Numerous oval shaped uniform papules and

macules with peripheral collateral scales appear abruptly(1-2cm of size)

• Distributed bilaterally symmetrically on • 1.Trunk• 2.Proximal portions of limbs

• On the back of trunk ,lesion show a fur tree or christmas tree like pattern

• Hanging curtain sign positive• When individual lesion is stretched along the

long axis ,the scales tend to fold across the lines of stretch

• Histological features• Focal parakeratosis• Mild acanthosis• Spongiosis• Exocytosis• Perivascular dermal infilitration with

lymphocytes

DIAGNOSIS

• Usually easily diagnosed by its morphology and distribution

• Can also occur as a manifestation of• 1.Secondary syphilis• 2.Drug reaction• 3.Internal malignancy(stomach)

TREATMENT

• Since self limiting ,no active treatment required

• Application of bland oils and avoidance of soap may relieve itching

• Severe itching -Oral antihistamines ,antipruritic lotions

PITYRIASIS LICHENOIDES

• Divided into two• 1.Pityrisis lichenoides chronica• 2.Pityriasis lichenoides et varioliformis acuta

(PLEVA) or Muscha-Habermann disease• They are two types of Parapsoriasis,other than

parapsoriasis en plaque

PARAPSORIASIS

• Includes a group of chronic,asymptomatic,maculopapular scaly eruptions of slow evolution

• Resistant to treatment

1.PITYRISIS LICHENOIDES CHRONICA

• Common type of parapsoriasis• Seen in children• Consists of discrete,scaly,erythematous• 1.Macules• 2.Papules• Papule shows a single layer of brownish scale• Removel of scale spoty hypopigmented

oval macule

Distribution – Bilaterally on sides of trunk and on thighs and upper arms

• Difference from psoriasis• 1.When one tries to remove the brownish

scale,it comes out as a wholeand not in layers• 2.Auspitz sign absent

Auspitz sign

• When scales are scrapped off completely in psoriasis patient ,the basement membrane is exposed and is seen as moist red surface

• Through which dilated capillaries are seen as red spots

• On further scrapping these capillaries at tips of elongated papillae are torn leading to multiple bleeding points(auspitz sign)

TREATMENT

• No active treatment indicated• Bland emollient application beneficial• Oral Tetracycline and PUVA therapy has been

reported effective

2.Pityriasis lichenoides et varioliformis acuta (PLEVA)

• Abrupt onset• Consists of erythematous

macules,papules,necrotic lesions,and few vesicles

• Eythematous papules tend to• 1.Crusting• 2.Necrosis• 3.Hemorrhage

• Distribution- trunk,flexor surface of upper extremities and the axillae

Histological features

• Dense lymphocytic perivascular infilitration in supficial dermis

• Erythrocytes trapped within epidermis

• Lesions heal leaving depressed varioliform (resembling smallpox) scar

• New lesions may erupt and disease can be chronic or subacute

TREATMENT

• Methotrexate• Tetracycline• Erythromycin• PUVA- May give relief in some patients

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