What causes unilateral acne to appear only on the left side of the face, from the patient's perspective?

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Last updated: March 11, 2025View editorial policy

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From the Guidelines

Acne appearing predominantly on the left side of the face is typically caused by external factors rather than internal ones, such as cell phone use, pillowcase hygiene, and environmental exposures, as suggested by general dermatological principles 1.

Causes of Unilateral Acne

The most common culprits behind unilateral acne on the left side of the face include:

  • Cell phone use, which can transfer oils, bacteria, and dirt to the skin during calls
  • Pillowcases that harbor bacteria and oils, especially if the individual tends to sleep on their left side
  • Habitual touching or resting of the hands on the left side of the face
  • Environmental factors like driving with the left side of the face exposed to sunlight or pollutants
  • Hair products that come into contact with the left side of the face more frequently due to hair parting

Recommendations for Management

To address this one-sided acne, the following measures are recommended:

  • Clean the phone regularly with alcohol wipes
  • Change pillowcases at least weekly
  • Avoid touching the face
  • Use a broad-spectrum sunscreen daily
  • Keep hair products away from the face
  • Implement a gentle skincare routine with salicylic acid or benzoyl peroxide to help treat existing breakouts If the problem persists despite these measures, it is advisable to consult a dermatologist, as it could indicate an underlying condition requiring professional treatment, as emphasized in the guidelines for the management of acne vulgaris 1.

From the Research

Unilateral Acne on the Left Side of the Face

There are no research papers that directly address the cause of unilateral acne appearing only on the left side of the face from the patient's perspective.

Possible Factors Contributing to Acne

  • Inflammation in the skin, as discussed in 2, may contribute to the development of acne
  • The pilosebaceous unit of the skin, as mentioned in 3, is the primary area affected by acne
  • Hormonal factors, as noted in 4 and 5, may also play a role in the development of acne, particularly in women
  • The use of certain medications, such as oral antibiotics and isotretinoin, as discussed in 3, 4, 6, and 5, may be effective in treating acne, but do not specifically address the cause of unilateral acne on one side of the face

Treatment Options for Acne

  • Topical retinoids, benzoyl peroxide, and azelaic acid, as mentioned in 2, 3, and 6, are commonly used to treat acne
  • Oral antibiotics, hormonal therapies, and isotretinoin, as discussed in 3, 4, and 5, may be used to treat more severe cases of acne
  • Combination therapy, as noted in 2 and 6, may be effective in treating acne by addressing its multifactorial pathophysiology

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diagnosis and treatment of acne.

American family physician, 2004

Research

Dermatology: how to manage acne vulgaris.

Drugs in context, 2021

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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