# Acne Vulgaris: From Mild to Severe

## Introduction

Acne vulgaris is the most common skin condition encountered in primary care, affecting approximately 85% of adolescents and persisting into adulthood in up to 50% of cases. Family physicians should be comfortable managing the full spectrum of acne severity, from comedonal acne to nodulocystic disease, and understand when to refer for isotretinoin therapy.

## Pathophysiology

Four key mechanisms drive acne formation. Follicular hyperkeratinization involves abnormal desquamation of keratinocytes that plugs the follicle. Excess sebum production is stimulated by androgens, particularly dihydrotestosterone (DHT). Cutibacterium acnes (C. acnes) colonization proliferates in the anaerobic, lipid-rich environment of the plugged follicle. Inflammation results from innate immune activation via toll-like receptors that triggers inflammatory cascades.

### Contributing Factors

Contributing factors include hormonal fluctuations related to puberty, the menstrual cycle, and PCOS. High-glycemic-index diets and possibly dairy consumption have emerging evidence as contributors. Mechanical irritation from helmets and chin straps, comedogenic cosmetics and occlusive products, and medications including corticosteroids, lithium, phenytoin, and androgens can all exacerbate acne.

## Classification and Grading

| Severity | Lesion Types | Description |
|----------|-------------|-------------|
| Mild | Comedones (open/closed) | Few inflammatory papules, predominantly comedonal |
| Moderate | Papules and pustules | Numerous inflammatory lesions, some comedones |
| Severe | Nodules and cysts | Deep, painful lesions; risk of scarring |

![Acne severity classification with clinical photographs](/images/acne-severity-classification.jpg)

## Management by Severity

### Mild Acne (Comedonal/Few Papules)

The cornerstone of therapy is a topical retinoid such as tretinoin (0.025 to 0.05%) or adapalene (0.1 to 0.3%). Benzoyl peroxide at 2.5 to 5% provides antibacterial activity and reduces resistance. The retinoid is applied at night and benzoyl peroxide in the morning. Results take 8 to 12 weeks, and patients should be counseled on realistic expectations.

### Moderate Acne (Papulopustular)

The combination of a topical retinoid and benzoyl peroxide remains foundational. A topical antibiotic such as clindamycin 1% is added in combination with benzoyl peroxide to prevent resistance. Oral antibiotics are considered for widespread disease, with doxycycline 50 to 100 mg daily as the preferred first-line and minocycline 50 to 100 mg daily as an alternative. Oral antibiotic courses should be limited to 3 to 4 months to minimize resistance. For adult females, combined oral contraceptives or spironolactone at 50 to 200 mg per day are effective options.

### Severe Acne (Nodulocystic)

Isotretinoin at 0.5 to 1 mg/kg/day for 15 to 20 weeks is the only therapy that addresses all four pathogenic factors. It requires enrollment in the iPLEDGE program for pregnancy prevention. Monitoring includes baseline and monthly pregnancy tests, lipid panel, liver function tests, and CBC. Common side effects include xerosis, cheilitis, myalgias, and elevated triglycerides. Referral to dermatology is appropriate for clinicians unfamiliar with isotretinoin management.

![Stepwise acne treatment algorithm by severity](/images/acne-treatment-algorithm.jpg)

## Special Populations

### Adult Female Acne

Adult female acne often presents along the jawline and chin with deep, tender nodules. Hormonal evaluation with testosterone and DHEA-S is indicated when there are signs of hyperandrogenism. Spironolactone is highly effective as adjunctive therapy, with potassium monitoring required. Combined OCPs containing norgestimate or drospirenone are preferred formulations.

### Acne in Skin of Color

Patients with skin of color have a higher risk of post-inflammatory hyperpigmentation (PIH). Retinoids help both acne and PIH but should be started at lower concentrations. Aggressive physical treatments that may worsen PIH should be avoided. Azelaic acid at 15 to 20% is an excellent option because it is anti-inflammatory, lightening, and comedolytic.

## Scarring Prevention and Management

Early, aggressive treatment is the best prevention for scarring. Atrophic scars (ice pick, boxcar, and rolling types) may benefit from procedures such as microneedling, fractional laser, or subcision performed by dermatology. Hypertrophic and keloid scars are treated with intralesional triamcinolone and silicone sheets. PIH is managed with topical retinoids, azelaic acid, vitamin C serums, and strict sun protection.

## Common Pitfalls

Common pitfalls include prescribing topical or oral antibiotics as monotherapy, which promotes resistance. Failing to include a topical retinoid in the regimen is another frequent error. Not counseling patients on the 8- to 12-week timeline for visible improvement leads to premature discontinuation. Overlooking acne's psychological impact is also problematic, and patients should be screened for depression and anxiety.

![Post-inflammatory hyperpigmentation management approach](/images/acne-pih-management.jpg)

## Key Clinical Pearls

Topical retinoids are the foundation of almost every acne regimen and should be continued as maintenance therapy even after antibiotics are stopped. Never prescribe topical or oral antibiotics without benzoyl peroxide, as this is the single most important step to prevent antibiotic resistance in acne. Isotretinoin is the most effective treatment for severe nodulocystic acne and should not be delayed when scarring is occurring. Adult female acne is common and responds well to hormonal therapies such as spironolactone and OCPs. The psychological impact of acne should always be assessed, as the condition is associated with significant depression, anxiety, and reduced quality of life.

## References

1. Zaenglein, A. L., et al. (2016). Guidelines of care for the management of acne vulgaris. *Journal of the American Academy of Dermatology*, 74(5), 945-973.
2. Barbieri, J. S., et al. (2019). Approaches to limit systemic antibiotic use in acne. *International Journal of Dermatology*, 58(3), 276-280.
3. Tan, A. U., Schlosser, B. J., & Paller, A. S. (2018). A review of diagnosis and treatment of acne in adult female patients. *International Journal of Women's Dermatology*, 4(2), 56-71.
4. Layton, A. M., et al. (2021). Isotretinoin for acne vulgaris: An updated review. *Clinical, Cosmetic and Investigational Dermatology*, 14, 1617-1626.