Is ultrasound used to diagnose acne lesions?

Ultrasound is Not Used for Diagnosing Acne Vulgaris

Ultrasound is not indicated or recommended for the diagnosis of acne vulgaris in clinical practice. The diagnosis of acne is primarily clinical, based on visual examination and identification of characteristic lesions.

Diagnostic Approach for Acne Vulgaris

Standard Diagnostic Method

• Acne diagnosis is made through clinical examination, identifying characteristic lesions such as:

  • Open or closed comedones (blackheads/whiteheads)
  • Papules
  • Pustules
  • Nodules
  • Distribution on face or trunk 1

• No imaging studies, including ultrasound, are mentioned in the 2024 American Academy of Dermatology guidelines for acne diagnosis 1

Clinical Grading Systems

• Several validated clinical grading systems exist for assessing acne severity:

  • Investigator Global Assessment (IGA)
  • Leeds revised acne grading system
  • Global Acne Grading System
  • Global Acne Severity Scale
  • Comprehensive Acne Severity Scale 1

• These visual assessment tools have demonstrated good agreement between clinician and patient ratings, eliminating the need for imaging 1

Research on Ultrasound in Acne

While ultrasound is not used for routine acne diagnosis, limited research has explored its potential applications:

1. Research Context Only: Some studies have investigated ultrasound for research purposes to understand acne morphology 2, but these findings have not translated to clinical practice recommendations

2. Monitoring Treatment of Acne Scars: High-frequency ultrasound has been studied for monitoring laser treatment outcomes for acne scarring, not for diagnosing active acne 3

3. Subclinical Features: Research has shown ultrasound can detect deeper tissue involvement in acne that may not be clinically apparent, but this remains investigational and not part of standard diagnostic protocols 2

Appropriate Use of Ultrasound in Dermatology

Ultrasound does have legitimate applications in dermatology, but acne diagnosis is not among them:

• Ultrasound is appropriate for evaluating superficial soft tissue masses, particularly those superficial to the deep fascia 1
• It can help differentiate solid from cystic lesions and localized masses from diffuse edema 1
• It's useful for confirming fluid content in suspected ganglion cysts or identifying fluid around tendons 1

Clinical Pitfalls to Avoid

1. Unnecessary Testing: Ordering ultrasound for acne diagnosis represents unnecessary healthcare utilization and cost without clinical benefit

2. Delayed Treatment: Pursuing imaging studies may delay initiation of appropriate acne therapy

3. Misdiagnosis Risk: Relying on imaging rather than clinical examination could lead to misclassification of acne severity or type

Proper Diagnostic Approach for Acne

The correct diagnostic approach for acne includes:

1. Visual examination to identify characteristic lesions (comedones, papules, pustules, nodules)
2. Assessment of distribution (face, trunk, or both)
3. Determination of severity using validated clinical grading systems
4. Consideration of patient age and lesion morphology (comedonal, inflammatory, mixed, nodulocystic) 4

Laboratory testing is generally not indicated unless there are signs of virilization or if the patient is prepubertal, in which case hormonal evaluation may be warranted 5.

In summary, while ultrasound technology continues to evolve in dermatology applications, current evidence and guidelines do not support its use for acne diagnosis, which remains a clinical diagnosis based on visual examination.