Skin-nontumor / Clinical dermatology
Other dermatoses
Pityriasis rosea

Author: Mowafak Hamodat, M.D., MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 20 July 2016, last major update August 2011

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PubMed Search: Pityriasis rosea

Cite this page: Pityriasis rosea. PathologyOutlines.com website. http://pathologyoutlines.com/topic/skinnontumorpityriasisrosea.html. Accessed December 8th, 2016.
Definition / General
  • Initially a single large "herald" patch, then a generalized rash 1 - 2 weeks later, lasting 2 - 6 weeks
  • Self-limited, possibly viral, benign lesion of children and young adults
  • Associated with pyrexia, headache, malaise, lymphadenopathy
  • Seasonal variation
  • Pityriasis means "fine scales"
Clinical Features
  • Papulosquamous lesions of trunk and extremities
  • Herald patch: single red scaly lesion that increases in size over 48 hours up to 2 - 10 cm
Clinical Images

Images hosted on PathOut servers:

Breast skin, courtesy of Mark R. Wick, M.D.

Micro Description
  • Non-specific subacute or chronic dermatitis with focal hyperkeratosis and angulated parakeratosis with slight acanthosis
  • Granular cell layer is absent beneath the foci of parakeratosis
  • Intraepidermal cytoid body may be present
  • Focal acantholytic dyskeratosis occasionally documented
  • Also lymphohistiocytic infiltrate around vessels of superficial plexus and slight spongiosis
  • Occasionally scattered eosinophils and erythrocytes within epidermis
Micro Images

Images hosted on PathOut servers:

Breast skin, courtesy of Mark R. Wick, M.D.

Differential Diagnosis
Additional References