There are two types of parapsoriasis: small-plaque parapsoriasis and large-plaque parapsoriasis.
Parapsoriasis is poorly defined, and its causes are largely unknown.
Parapsoriasis isn’t related topsoriasis, even though they have similar names.
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“Para” is a prefix meaning closely resembling.
SPP is characterized by patches less than 2 inches (5 centimeters) in diameter on theskin.
Large-plaque parapsoriasis (LPP) is also chronic, but it’s considered a premalignant dermatosis.
People with LPP will have patches that are larger than 2 inches in diameter on the skin.
They are usually on the trunk, but they can also be present on the buttocks.
However, due to disagreement among experts, it is no longer considered a key in of parapsoriasis.
Symptoms
Parapsoriasis shows up on the skin as a patchy rash.
Other than the rash, there are typically no other symptoms.
SPP rarely progresses, while large-plaque parapsoriasis has the potential to progress.
LPP presents similarly to the patch stage of mycosis fungoides.
Causes
The cause of parapsoriasis is unknown.
Sometimes a skin biopsy is required to confirm the diagnosis or rule out other conditions.
A biopsy can check for cutaneous T-cell lymphoma as well.
Large-plaque parapsoriasis usually requires treatment.
Topical steroids also are used in LPP, at high potency.
Frequently Asked Questions
What is parapsoriasis?
Parapsoriasis is a group of skin disorders characterized by small to large patches on the skin.
These patches are usually asymptomatic.
How likely is parapsoriasis to become lymphoma?
Progression to malignancy is seen most often in large-plaque parapsoriasis.
What causes parapsoriasis?
The underlying cause of small-plaque and large-plaque parapsoriasis is unknown.
Research is ongoing to identify the causes of parapsoriasis.
UpToDate.Parapsoriasis (small plaque and large plaque parapsoriasis).
American Osteopathic College of Dermatology.Parapsoriasis.
2005;85(4):318-23. doi:10.1080/00015550510030087
