Atrophic acne scars have lost collagen from the healing response and are the most common type of acne scar (account for approximately 75% of all acne scars).[32][33] They may be further classified as ice-pick scars, boxcar scars, and rolling scars.[31] Ice-pick scars are narrow (less than 2 mm across), deep scars that extend into the dermis.[32] Boxcar scars are round or ovoid indented scars with sharp borders and vary in size from 1.5–4 mm across.[32] Rolling scars are wider than icepick and boxcar scars (4–5 mm across) and have a wave-like pattern of depth in the skin.[32]

Risk factors for the development of acne, other than genetics, have not been conclusively identified. Possible secondary contributors include hormones, infections, diet and stress. Studies investigating the impact of smoking on the incidence and severity of acne have been inconclusive.[2][38][39] Sunlight and cleanliness are not associated with acne.[14]
Cystic acne is the most severe form of acne vulgaris and can be caused by a variety of factors. This type of acne sees painful lesions develop deep within the skin, which could result in permanent scarring or hyperpigmentation. Cystic acne is easily diagnosed due it its pronounced, inflamed lesions. However, you should consult a dermatologist to rule out other skin conditions which might mimic acne such as rosacea, psoriasis or perioral dermatitis.

Many different treatments exist for acne. These include alpha hydroxy acid, anti-androgen medications, antibiotics, antiseborrheic medications, azelaic acid, benzoyl peroxide, hormonal treatments, keratolytic soaps, nicotinamide, retinoids, and salicylic acid.[75] They are believed to work in at least four different ways, including the following: reducing inflammation, hormonal manipulation, killing P. acnes, and normalizing skin cell shedding and sebum production in the pore to prevent blockage.[76] Common treatments include topical therapies such as antibiotics, benzoyl peroxide, and retinoids, and systemic therapies including antibiotics, hormonal agents, and oral retinoids.[20][77]
Ablative lasers deliver an intense wavelength of light to the skin, removing thin outer layers of the skin (epidermis). In addition, collagen production is stimulated in the underlying layer (the dermis). Patients are typically numbed with local anesthetic and the ablation is done as an outpatient procedure. CO2 and erbium are the ablative lasers most often used for acne scar treatment.
Clascoterone is a topical antiandrogen which has demonstrated effectiveness in the treatment of acne in both males and females and is currently in the late stages of clinical development.[120][121][122][123] It has shown no systemic absorption or associated antiandrogenic side effects.[122][123][124] In a direct head-to-head comparison, clascoterone showed greater effectiveness than topical isotretinoin.[122][123][124] 5α-Reductase inhibitors such as finasteride and dutasteride may be useful for the treatment of acne in both males and females, but have not been thoroughly evaluated for this purpose.[1][125][126][127] In addition, the high risk of birth defects with 5α-reductase inhibitors limits their use in women.[1][126] However, 5α-reductase inhibitors can be combined with birth control pills to prevent pregnancy, and are frequently used to treat excessive hair in women.[125] There is no evidence as of 2010 to support the use of cimetidine or ketoconazole in the treatment of acne.[128]
Pimples are raised red spots with a white center that develop when blocked hair follicles become inflamed or infected with bacteria. Blockages and inflammation that develop deep inside hair follicles produce cystlike lumps beneath the surface of your skin. Other pores in your skin, which are the openings of the sweat glands, aren't usually involved in acne.
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