What diagnostic tests are used for acne?

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From the Guidelines

Diagnostic Tests for Acne

Acne diagnosis primarily involves a thorough medical history and physical examination to determine the severity and type of acne 1.

Initial Assessment

The Physician Global Assessment (PGA) or other scales like the Investigator Global Assessment (IGA) are used to assess acne objective severity consistently 1. The IGA scale, which ranges from 0-4 (clear, almost clear, mild, moderate, and severe), is commonly used in the US and demonstrates good agreement between clinician and patient ratings 1.

Further Testing

In cases of moderate to severe acne, or if initial treatments are ineffective, further testing may be necessary, including:

  • Blood tests to check for underlying hormonal imbalances, such as polycystic ovary syndrome (PCOS) in females, which may involve measuring testosterone, dehydroepiandrosterone sulfate (DHEAS), and other hormone levels 1.
  • Digital photography, as well as fluorescent photography, polarized light photography, video microscopy, and multispectral imaging modalities may also be used to measure acne severity 1.
  • Microbiologic testing may be considered for patients presenting with specific types of acne, such as Gram-negative folliculitis or pityrosporum folliculitis 1.

Importance of Healthcare Provider

It's crucial to work with a healthcare provider to determine the best course of treatment and testing based on individual needs and the severity of acne 1.

From the Research

Diagnostic Tests for Acne

The diagnosis of acne is typically made based on a history and physical examination 2. The following are some diagnostic tests and methods used to assess acne:

  • History and physical examination: The diagnosis of acne usually can be made on the basis of a history and physical examination 2
  • Screening tests: Screening tests, particularly bone age, may be considered to support the clinical diagnosis in younger children 2
  • Lesion counting: Lesion counting is a method used to assess acne severity, which involves counting the number of lesions on the skin 3
  • Global gradings: Global gradings are another method used to assess acne severity, which involves grading the severity of acne based on the number and type of lesions 3
  • Photography: Photography, including fluorescence photography, polarized light photography, and multispectral imaging, can be used to objectively assess acne severity 3
  • Video microscopy: Video microscopy is a technique used to assess acne severity by visualizing the skin lesions in detail 3

Limitations of Diagnostic Tests

The diagnostic tests and methods used to assess acne have some limitations, including:

  • Subjectivity: The global gradings and lesion counting methods have some subjectivity involved, which can lead to variability in assessment 3
  • Cost and complexity: The use of photography, video microscopy, and multispectral imaging can be costly and require complex and sophisticated apparatus 3
  • Time-consuming: The imaging process for some of these methods can be time-consuming 3

Classification of Acne

Acne can be classified based on the number and type of skin lesions, as well as the severity of the disease 4, 5. The classification of acne includes:

  • Mild acne: Characterized by a small number of non-inflammatory lesions 5
  • Moderate acne: Characterized by a moderate number of inflammatory lesions 5
  • Severe acne: Characterized by a large number of inflammatory lesions and potential scarring 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diagnosis and evaluation of acne.

Seminars in cutaneous medicine and surgery, 2010

Research

Objective assessment of acne.

Clinics in dermatology, 2017

Research

Acne Vulgaris: Diagnosis and Treatment.

American family physician, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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