font size

Pityriasis Rosea (cont.)

Medical Author:
Medical Editor:

How is pityriasis rosea diagnosed?

Pityriasis rosea is usually diagnosed by the skin appearance, particularly the onset of the distinct large herald patch and the symmetrical Christmas tree presentation. Also, the herald patch tends to have a unique, fine scale with a definite border, the so-called "collarette." To rule out other types of skin disorders, a physician may scrape the skin and examine the scales under the microscope after exposure to potassium hydroxide or "KOH" to detect fungus infection that could mimic pityriasis. Also, blood tests including rapid plasma reagent (RPR) may be done to detect secondary syphilis, which also may mimic pityriasis. In some cases, a skin biopsy may be required to detect fungus and other types of rashes.

What are some common misdiagnoses of pityriasis rosea?

The first herald patch of pityriasis rosea may look very similar in appearance to ringworm (tinea corporis). Pityriasis has also been mistaken with eczema and psoriasis, which can occur as similar scaly patches, but not in the same distribution as pityriasis rosea.

Pityriasis rosea may be misdiagnosed as

  • psoriasis,
  • eczema,
  • fungal infection (tinea corporis),
  • secondary syphilis,
  • drug eruption (a diffuse body rash caused commonly by a reaction to a medications like an oral antibiotic),
  • fixed drug eruption (a single small, circular or oval patch of skin rash caused by taking a medication),
  • pityriasis lichenoides chronica,
  • parapsoriasis,
  • HIV-associated rash,
  • folliculitis.
Medically Reviewed by a Doctor on 8/29/2014

Patient Comments

Viewers share their comments

Pityriasis Rosea - Treatments Question: What treatment has been effective for your pityriasis rosea?
Pityriasis Rosea - Symptoms Question: What symptoms and signs did you experience with pityriasis rosea?
Pityriasis Rosea - Experience Question: Please describe your experience with pityriasis rosea.
Pityriasis Rosea - Prognosis Question: What is your pityriasis rosea prognosis?
Source: MedicineNet.com
http://www.medicinenet.com/pityriasis_rosea/article.htm

Women's Health

Find out what women really need.

advertisement
advertisement
Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations