Acne: Causes, Types and Treatment
Acne: Causes, Types and Treatment — a common inflammatory condition of the pilosebaceous unit (the pore and its oil gland). It develops when excess sebum, dead skin cells and the bacterium C. acnes clog pores, leading to blackheads, whiteheads, papules, pustules, nodules or cysts.
Key points
- Four drivers combine: excess oil, sticky dead-cell buildup, C. acnes bacteria and inflammation.
- Non-inflammatory acne (blackheads, whiteheads) differs from inflammatory acne (red papules, pustules, painful nodules/cysts).
- Evidence-based ingredients include salicylic acid, benzoyl peroxide, azelaic acid, retinoids and niacinamide.
- Hormones, some cosmetics, friction and certain medications can trigger or worsen breakouts; picking increases scarring risk.
In this guide
- Hormonal Acne
- Adult Acne
- Teenage Acne
- Cystic Acne
- Comedonal Acne
- Fungal Acne (Malassezia Folliculitis)
- Body Acne
- Back Acne (Bacne)
- Chest Acne
- Post-Acne Marks (PIE and PIH)
- Acne Scarring
- Atrophic Acne Scars
- Hypertrophic and Keloid Scars
- Blackheads
- Whiteheads
- Closed Comedones
- Sebaceous Filaments
- Enlarged Pores
- Congested Skin and Clogged Pores
- Excess Oil and Shine
- Melasma
- Post-Inflammatory Hyperpigmentation
- Sun Spots and Solar Lentigines
- Freckles
- Uneven Skin Tone
- Dark Spots
- Periorbital Hyperpigmentation
- Rosacea
- Facial Redness and Flushing
- Broken Capillaries and Telangiectasia
- Perioral Dermatitis
- Seborrheic Dermatitis
- Eczema (Atopic Dermatitis)
- Contact Dermatitis
- Psoriasis
- Keratosis Pilaris
- Milia
- Wrinkles
- Fine Lines
- Crow's Feet
- Forehead Lines
- Nasolabial Folds
- Loss of Firmness and Elasticity
- Sagging Skin
- Skin Laxity
- Volume Loss and Facial Aging
- Dull and Tired-Looking Skin
- Uneven Skin Texture
- Rough Skin
- Flaky and Peeling Skin
- Skin Dehydration
- Tightness and Discomfort
- Dark Circles Under the Eyes
- Under-Eye Bags and Puffiness
- Crepey Skin
- Age Spots on Hands
- Neck Aging and Tech Neck
- Chest and Décolletage Aging
- Stretch Marks
- Cellulite
- Ingrown Hairs
- Razor Burn and Shaving Irritation
- Folliculitis
- Hyperhidrosis (Excessive Sweating)
- Body Odor and Skin
- Chapped and Dry Lips
- Lip Pigmentation
- Sparse and Thinning Brows
- Skin Sensitivity and Stinging
- Allergic Reactions and Hives
- Sunburn
- Photodamage and Photoaging
- Actinic Keratosis
- Windburn and Cold-Weather Damage
- Maskne (Mask-Related Acne)
- Barrier Damage and Over-Exfoliation
- Retinoid Purging
- Skin Purging vs Breaking Out
- Dry Patches on the Face
- Oily T-Zone
- Combination-Skin Concerns
- Blocked Sebaceous Glands
- Whitening and Brightening Concerns
- Sallow and Yellow-Toned Skin
- Redness After Exfoliation
- Skin Barrier Itch
- Winter Skin
- Summer Breakouts
- Sweat-Related Breakouts
- Hormone-Related Pigmentation
- Skin Changes in Pregnancy
- Skin Changes in Menopause
- Under-Eye Fine Lines
- Eyelid Skin Concerns
Frequently asked
What actually causes acne?
A combination of excess sebum, clogged pores from dead skin cells, C. acnes bacteria and inflammation — not simply "dirty" skin or a single food.
Which ingredients treat acne best?
Salicylic acid, benzoyl peroxide, azelaic acid and topical retinoids are the most evidence-backed; persistent or cystic acne warrants a dermatologist's advice.
Related topics
This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.
