pityriasis rubra Flashcards
lesion. what virus reinfection.
■ An acute exanthematous eruption with a distinctive morphology and o ten with a characteristic sel -limited course.
■ Initially,asingle(primary,or“herald”)plaquelesiondevelops,usuallyonthetrunk;1or2weekslater a generalized secondary eruption develops in a typical distribution pattern.
■ The entire process remits spontaneously in 6 weeks.
■ Reactivation o human herpesvirus-7 (HHV-7) and HHV-6 is the most probable cause.
age m
AGEOFONSET en to 43 years, but can occur rarely in in ants and old persons.
SEASON Springand all
course of lesions
SKINLESIONS HeraldPatch. Occursin80%o patients, preceding exanthem. Oval, slightly raised plaque or patch 2 to 5 cm, salmon-red,
ne collarette scale at periphery; may be mul- tiple (Fig. 3-19A).
Exanthem. One to two weeks a er herald patch. Fine scaling papules and patches with marginal collarette (Fig. 3-19B). Dull pink
or tawny. Oval, scattered, with characteristic distribution ollowingthelineso cleavagein
a “Christmas tree” pattern (Fig. 3-20). Lesions usuallycon nedtotrunkandproximalaspects o thearmsandlegs.Rarelyon ace. AtypicalPityriasisRosea. Lesionsmaybe present only on the ace and neck.
Spontaneous remission in 6 to 12 weeks or less. Recurrences are uncommon
Dp. absence of what cells
Patchy or di use para- keratosis,absenceo granularlayer,slight acanthosis, ocalspongiosis,andmicroscopic vesicles. Occasional dyskeratotic cells with an eosinophilic homogeneous appearance. Edema o dermisandperivascularin ltrateo mono- nuclear cells
best treatment option
SYMPTOMATIC Oral antihistamines and/or topicalantipruriticlotions orrelie o pruritus.
opical glucocorticoids. May be improved by UVB phototherapy or natural sunlight expo- sure i treatment is begun in the rst week o eruption.Ashortcourseo systemicglucocor- ticoids is the best option.
