Auspitz Sign in Psoriasis Diagnosis: What Dermatologists Need to Know

April 15, 2024

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The Auspitz sign has long been considered a classic clinical feature of psoriasis. First described by Austrian dermatologist Heinrich Auspitz in the 19th century, this sign refers to pinpoint bleeding that occurs when psoriatic scales are scraped away from the skin’s surface.

While once regarded as a reliable indicator of psoriasis, emerging research suggests the Auspitz sign has limitations in definitively diagnosing psoriasis. When present alongside other characteristic plaque features, it can support a psoriasis diagnosis – but absence does not rule out this condition either.

Overview of the Auspitz Sign

The Auspitz sign in psoriasis refers to tiny punctate bleeding spots visible when white, silver-colored psoriatic scales are gently scraped off areas of skin. This sign occurs due to architectural changes in small blood vessels under psoriatic plaques.

In particular, blood vessels in these areas become:

  • Elongated
  • Twisted
  • Dilated

This distortion makes vessels prone to rupture and leak when the overlying scales are disrupted. The skin underneath is also thinned, contributing to easy damage. The combined effect is dot-like bleeding points seen in the Auspitz sign.

History of the Auspitz Sign

Viennese dermatologist Dr. Heinrich Auspitz first characterized what would become known as the Auspitz sign in the late 1800s. In his 1884 textbook on skin diseases, Auspitz described a “punctiform bleeding” occurring after scraping off scales from psoriatic lesions.

For decades after, medical textbooks upheld the Auspitz sign as a distinguishing and pathognomonic feature of psoriasis. The sign was believed sensitive and specific for definitively diagnosing this condition.

However in the late 20th century, researchers began questioning the reliability of the Auspitz sign as a diagnostic marker. Emerging evidence revealed flaws in its sensitivity and specificity.

Limitations of the Auspitz Sign

While once considered a hallmark of psoriasis, major reviews show the Auspitz sign has constraints as a diagnostic tool. Key limitations include:

Low sensitivity

Multiple studies reveal the Auspitz sign is often absent even in confirmed psoriasis cases. Rates of positivity range widely from 26 to 70% in psoriatic populations. This indicates low sensitivity – many true cases test negative.

Low specificity

The sign also occurs in several other skin conditions beyond psoriasis. These include seborrheic dermatitis, actinic keratoses and Darier’s disease. This lack of specificity means false positive results occur.

Current Role in Psoriasis Diagnosis

Due to its low sensitivity and specificity, the Auspitz sign no longer serves as a reliable standalone test for psoriasis. However, it still plays a contributing role in diagnosis when present alongside other clinical criteria.

According to the American Academy of Dermatology, key diagnostic features of psoriasis include:

  • Sharply demarcated erythematous plaques
  • Silvery white scaling
  • Symmetric distribution
  • Chronic recurrent course
  • Koebner phenomenon
  • Family history

If pinpoint bleeding occurs when scraping off scales from plaques with features above, this reinforces a psoriasis diagnosis. But absence of bleeding does not exclude psoriasis.

Procedures for Eliciting the Auspitz Sign

Traditional method

Doctors traditionally used a simple hands-on method to check for the Auspitz sign with just gloves and glass slides. After isolating an area of suspected psoriatic plaque, the doctor scrapes off overlaying scales using a slide’s blunt edge or fingernail. Gently removing white scales layers by layer allows visualizing any pinpoint bleeding underneath.

Dermoscopic method

Today, dermatologists often use magnifying devices called dermatoscopes to better visualize the Auspitz sign. A dermascope can examine skin at ~10 times magnification without trauma associated with scraping. This allows detecting leaks from fragile blood vessels under thin psoriatic skin without causing much discomfort.

Key Takeaways

  • The Auspitz sign refers to tiny bleeding spots seen when psoriatic scales are removed and is due to changes in plaques’ blood vessels.
  • Once considered a reliable indicator of psoriasis, the sign has low sensitivity and specificity based on current evidence.
  • When present together with other clinical criteria, the Auspitz sign can support a psoriasis diagnosis but absence does not exclude psoriasis.
  • Traditionally checked via skin scraping, dermascopes now allow a magnified view of punctate bleeding with less discomfort.

FAQs

What is the Auspitz sign?

The Auspitz sign refers to pinpoint bleeding that becomes visible when white scales are gently lifted off areas of psoriatic plaques. Underneath, small blood vessels are fragile and prone to rupturing.

Is the Auspitz sign unique to psoriasis?

No, the Auspitz sign also occurs in several other skin conditions like actinic keratosis, Darier’s disease and seborrheic dermatitis. It is not exclusively indicative of psoriasis.

Why did the Auspitz sign was once considered a hallmark of psoriasis?

When first characterized by Dr. Auspitz in the 1800s, the sign was believed to distinguish psoriasis from other potential diagnoses. But modern research shows flaws in its sensitivity and specificity.

How accurate is the Auspitz sign for diagnosing psoriasis?

Based on current evidence, the Auspitz sign alone cannot definitively diagnose psoriasis due to poor sensitivity and specificity. But combined with clinical features like plaques and scaliness, it can support a psoriasis diagnosis.

What is the best way to check for the Auspitz sign?

Dermatoscopes provide the most accurate view of pinpoint bleeding by allowing 10x magnified visualization of punctate spots underneath scales, without scraping that may hurt sensitive skin.

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