Acne

Acne vulgaris is a chronic inflammatory skin condition that primarily affects teenagers, though adults are also affected. Acne vulgaris is characterized by inflamed skin lesions, such as papules, pustules, and comedones (whiteheads and blackheads), which occur when oil and dead skin cells clog hair follicles, which become inflamed.

The main signs and symptoms of acne vulgaris are inflamed and clogged hair follicles, especially on the face. They can appear in many forms and colors:

• Whiteheads (closed plugged pores)
• Blackheads (open plugged pores, which appear black due to oxidized melanin)
• Papules (tender red bumps)
• Pustules (containing pus)
• Nodules (cystic lesions appearing as painful lumps beneath the skin)

Diagnosing acne vulgaris can be difficult because it is often confused with other skin conditions like angiofibroma, folliculitis, and rosacea, due to their similar signs and symptoms.

There is no validated and universal way to diagnose acne vulgaris. Many definitions and grading scales exist, and most grading scales use photographs and the number of acne lesions to quantify the severity of acne vulgaris from mild to severe.^[1]

• Mild acne: noninflammatory lesions, few inflammatory lesions, or both
• Moderate acne: more inflammatory lesions, occasional nodules that form as hard, painful lesions, and mild scarring
• Severe acne: extensive inflammatory lesions, nodules, and scarring, ongoing moderate acne that has not improved with treatment after 6 months, or any acne that causes serious psychological distress^[2]

The diagnosis of acne vulgaris should be based on the clinical judgment of a medical professional.

The current treatments for acne vulgaris consists of three approaches:^[3]

1. Topicals treatments (e.g., antibiotics, benzoyl peroxide, dapsone, retinoids, or azelaic acid)
2. Oral treatments (e.g., antibiotics, hormonal agents, and the current gold standard isotretinoin)
3. Physical interventions (e.g., chemical peels, microneedling, and laser therapy)

The goal of treatment is to reduce the leading causes of acne vulgaris: excess sebum and keratin production, increased inflammation, and overgrowth of Cutibacterium acnes, the main bacterial species responsible for acne.

Supplementing with certain minerals, vitamins, and other compounds may improve acne. The most well-supported supplements include zinc, vitamin D, vitamin B5, fish oil, green tea extract, and probiotics. However, some supplements were shown to worsen acne symptoms or lead to breakouts, especially when taken at high doses. These include iodine, whey protein, vitamin B6, and vitamin B12.

Diet can have positive or negative effects on acne vulgaris. The most studied dietary factors that influence acne are:^[3]

• Glycemic index: A low glycemic index diet can improve symptoms of acne vulgaris.
• Omega-3: Supplementation with omega-3 fatty acids can improve the symptoms of acne vulgaris.
• Probiotics: Supplementation with probiotics can improve the symptoms of acne vulgaris.
• Dairy: Consumption of dairy and whey protein powder, in particular, can worsen acne severity.

Many nonmedical treatments have been researched for acne vulgaris due to the prevalence of the condition, however, the evidence for most alternative treatments is either nonexistent or low in quality.^[4]

For instance, there is some weak evidence that tea tree oil and bee venom may reduce total skin lesions in acne vulgaris.

In contrast, acupuncture, herbal medicine, and wet-cupping therapy were not found to be helpful to ease the symptoms of acne vulgaris.

Notably, alternative treatments may lead to adverse effects that can worsen acne vulgaris or lead to other health problems.

The exact causes of acne vulgaris are not yet clear. Genetics may be the main factor. Other possible causes include hormones, infections, diet, and stress. Studies investigating the effects of smoking, sunlight exposure, and general hygiene have been inconclusive.

In contrast, the development of acne vulgaris on a cellular level is better understood. The pathogenesis of acne vulgaris revolves around four key factors:^[3]

1. Excess sebum production
2. Overgrowth of Cutibacterium acnes, the main bacterial species infecting clogged hair follicles
3. Hyperkeratinization, or excessive production of keratin, is one of the main structural proteins that stick skin cells together
4. Inflammatory processes