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Medical Author:

Gary W. Cole, MD, FAAD

Gary W. Cole, MD, FAAD

Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• Pityriasis rosea facts
• What is pityriasis rosea?
• Who gets pityriasis rosea?
• What causes pityriasis rosea?
• What are pityriasis rosea symptoms and signs?
• How is pityriasis rosea diagnosed?
• What are some common misdiagnoses of pityriasis rosea?
• What is the treatment for pityriasis rosea?
• What home remedies can I use for pityriasis rosea?
• Can pityriasis rosea be prevented?
• What is the prognosis for pityriasis rosea?
• Where can I find more information and facts about pityriasis rosea?
• Patient Comments: Pityriasis Rosea - Experience
• Patient Comments: Pityriasis Rosea - Treatments
• Patient Comments: Pityriasis Rosea - Symptoms
• Find a local Dermatologist in your town
• Pityriasis Rosea Index

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 use a quick prep fungal test called 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.

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.