Acne tends to resolve between the ages of 30- to 40-years. However, it can persist into, or develop for the first time during adulthood. The prevalence of acne in girls increases from 61% at age 12 to 83% at age 16. In boys, the prevalence increases similarly - from 40% at age 12 to 95% at age 16. Acne outbreaks often worsen before the menstrual period, especially in women older than 30 ^1,2 

Pathogenesis and severity of acne 

Acne is characterised by chronic or recurrent development of comedones (open comedones referred to as blackheads and closed comedones referred to as whiteheads), erythematous, papules, pustules as well as nodules. The most commonly affected area is the face. Other areas susceptible to the development of acne include the neck, trunk, and proximal upper extremities.^1,3 

The pathogenesis of acne is multifactorial. Key components include:³  

• Follicular hyperkeratinisation 
• Inflammation 
• Propionibacterium acnes (also referred to as Cutibacterium acnes) bacteria colonisation 
• Sebum production. 

Although there is no standard classification, acne is generally classified as mild, moderate, and severe:³ 

• Grade 0 (clear skin)  
• Grade 1 (almost clear) 
• Grade 2 (mild severity 
• Grade 3 (moderate severity) 
• Grade 4 (severe).  

Mild acne is more common in people of European descent, whereas severe acne tends to be more common in those of African descent. Temperature and humidity contribute to the severity of the outbreaks. Outbreaks are more common during the summer and rainy seasons.^1,4  

How is acne diagnosed? 

Diagnosis is clinical and is based on the characteristics of the lesions (closed comedones, open comedones, inflammatory papules, pustules, inflamed nodules, and inflamed nodulocystic lesions) and their distribution (face, neck, back, chest, shoulders, or upper arms). Laboratory investigations are usually not necessary unless clinically indicated.¹  

There are several different forms of acne. These include:¹  

• Acne conglobata: affects young males and mostly affects the posterior back and chest but may extend to the buttocks. Classified as a severe, destructive, and highly inflammatory form of acne. Presents as grouped and polyporous comedones, nodulocystic lesions, burrowing, interconnecting deep-seated abscesses, and draining sinus tracts with purulent, foul-smelling discharge. The condition may lead to significant scarring.  
• Acne fulminans: a rare form of acne, which typically develops in individuals aged 13- to 16-years with a male-to-female ratio of 3:1. Characterised by the sudden onset of painful, haemorrhagic pustules, friable plaques, and large, necrotic, ulcerating nodules mainly on the back but may involve the chest, face, neck, and shoulders. Patients often experience other symptoms such as malaise, fever, chill, weight loss, diffuse myalgia, polyarthralgia, erythema nodosum, hepatosplenomegaly, bone lesions, increased inflammatory markers (eg leukocytosis, neutrophilia, elevated erythrocyte sedimentation rate or C-reactive protein) and elevated liver enzymes. Comedones are uncommon and polyporous comedones are absent. May be an isolated disorder and may be triggered by syndromes such as pyogenic arthritis, pyoderma gangrenosum, synovitis, pustulosis, hyperostosis, osteitis, pyogenic arthritis, and hidradenitis suppurativa.  
• Acne excoriée (also known as ‘picker’s acne’): caused by excessive picking and scratching of the acne lesions. It is more common in young women. Typically presents with comedones and inflammatory papules. Picking or scratching the acne lesions exacerbates the acne lesions and may result in excoriations, erosions, ulcerations, scabs, and scars.  

• Acne tarda: is the late onset of acne or persistence/relapse of acne in women in their thirties and forties and is associated with premenstrual breakouts. Late-onset acne tends to involve the chin, jawline, and neck with a predominance of inflamed papules and pustules with relatively few comedones.  

How is acne treated? 

Diet, lifestyle factors, and neuroendocrine regulatory mechanisms may contribute to the onset or persistence of acne. Therefore, targeting as many factors as possible increases the likelihood of successful results.¹  

A stepwise, escalated management approach is recommended based on the extent and severity of acne, as well as the response to treatment:¹ 

Step 1: Proper skin care 

The American Academy of Dermatology (AAD) recommends:^1,5 

• Keep the face clean: patients should be advised to use gentle skin cleansers rather than scrubs and soaps (especially harsh or drying soaps). Patients can also be advised to pat dry their face after washing rather than rubbing and exfoliating. They should avoid aggressive scrubbing of the skin.  
• Choose the right skin care products: use gentle skin care products and ones that are non-comedogenic. Avoid products that can irritate the skin (eg contain alcohol), including astringents, toners, and exfoliants. These products can dry the skin and make acne appear worse. The use of oil-free moisturisers is recommended. 
• Shampoo regularly: oil from hair can cause acne on the forehead. Patients with oily hair should be encouraged to shampoo more often than they currently do and keep hair away from the face. 
• Stick to treatment: trying new acne treatments too often can irritate the skin and cause breakouts. Patients should be encouraged to stick with a treatment to give it time to work. It may take several weeks to a few months to see a difference. 

• Keep hands off: patients should be advised not to touch their faces throughout the day because this can cause acne breakouts. While it can be tempting to pick, pop, or squeeze your acne, doing so will make the acne take longer to clear and increase the risk of scarring and post-inflammatory hyperpigmentation. 
• Stay out of the sun and tanning beds: tanning damages the skin worsens acne and increases the risk of skin cancer. Some acne medications can also make the skin extremely sensitive to damaging ultraviolet rays from the sun and tanning beds. If tanning cannot be avoided (eg outdoor workers) patients should be advised to wear sun-protective clothing (indicated by an ultraviolet protection factor number on the label) and apply a broad-spectrum, water-resistant, oil-free sunscreen with an SPF of 30 or higher.  

Step 2: Topical therapies 

Topical agents are the first-line treatment for mild-to-moderate acne and can be used as combination therapy for more severe acne. The choice of therapy should be based on the patient’s age, site, severity of acne, efficacy, safety, cost of the medication, and patient preference.  

Generally, patients with dry skin prefer lotions or creams whereas patients with oily skin may prefer gels. Topical retinoids (eg tretinoin) are the agents of choice for the treatment and maintenance therapy of patients with mild-to-moderate acne.  

Topical retinoids are usually applied once daily, preferably at night, due to the photolability and photosensitivity associated with their use. Some patients may have an exacerbation of acne (known as a ‘retinoid flare) during the first month of treatment.  

To minimise irritation and ensure treatment adherence, patients should be started on low concentrations of topical retinoids, which can then be slowly titrated.  

Numerous studies have shown that topical retinoids are safe and efficacious for the treatment of acne. It should be noted that they are slower to work, so advise the patient that perseverance is key.  

Apart from being effective and safe, other benefits of topical retinoids include improvement of skin tone and hyperpigmentation and reduction of atrophic scarring. Optimal results can be obtained when they are used in combination with an antimicrobial agent.  

Step 3: Oral therapies 

Antibiotics 

Oral antibiotics are an important therapy for acne unresponsive to topical therapy and the more inflammatory types of acne lesions. They are particularly useful for acne involving the back because of the difficulties of applying topical treatments to large areas that are difficult to reach.  

Oral antibiotics have anti-inflammatory properties and work by inhibiting neutrophil chemotaxis and altering macrophage and cytokine production.  

Tetracyclines (doxycycline, minocycline, sarecycline) are preferred because of greater efficacy and better tolerability. The use of tetracyclines is contraindicated for pregnant individuals, individuals with childbearing potential, and children younger than eight.  

Azithromycin (500mg one to three times per week) and erythromycin (500mg twice a day) are the macrolides most often used when tetracyclines are contraindicated (eg children ≤8 years of age, pregnant women, or breastfeeding mothers).  

Isotretinoin 

In the past, concerns about a causal relationship between isotretinoin therapy and depression, suicidal ideation, and inflammatory bowel disease have led to uncertainties about the use of the agent. However, newer studies have found no link. 

It should be noted though, that isotretinoin is teratogenic and is, therefore, contraindicated in women of childbearing until pregnancy is excluded and an effective form of contraception is being used during treatment and for one month after stopping the medication.  

Isotretinoin is also contraindicated in individuals with a history of hypersensitivity to isotretinoin or its component. Concomitant treatment with isotretinoin and tetracyclines should be avoided because of the risk of pseudotumour cerebri. Additionally, vitamin A supplementation may increase the side effects of isotretinoin and should therefore be avoided.  

According to the AAD, about 85% of patients see permanent clearing after one course of isotretinoin.⁶ 

Hormonal therapies 

For women in post-menarche with acne, hormonal therapy is a therapeutic option. The use of oestrogens in the form of oral contraceptives in the treatment of acne is based on the ability of oestrogen to suppress the stimulatory effect of androgens on pilosebaceous units leading to decreased size and function of sebaceous glands with a resultant reduction in sebum production and keratinous material accumulation.  

The use of oral contraceptives should be considered in women in post-menarche typically over the age of 15 years with moderate-to-severe, recalcitrant, pustulocystic, or nodulocystic acne who do not respond or are intolerant to conventional therapy as well as in those who experience premenstrual flares, especially along the jawline and lower face, and in those with evidence of hyperandrogenism (eg hirsutism, oligomenorrhoea) such as those with the polycystic ovarian syndrome.  

For post-pubertal women who desire a contraception method and who have no contraindications to oral contraceptives, an oral contraceptive is preferred to spironolactone as hormonal therapy for acne, though the two are often combined for enhanced efficacy. Oral contraceptives containing both oestrogen and progestin rather than progestin-only contraceptives should be used. 

Spironolactone should be considered in women who use oral contraceptives, are refractory to topical acne therapy, have hyperandrogenism, or present with late-onset (>25 years old) acne.  

Pregnancy should be avoided and adequate contraceptive measures should be instituted during spironolactone therapy due to concerns about the feminisation of the male foetus.  

Corticosteroids 

Oral corticosteroids may be considered as an adjunct treatment of acne fulminans, aggressive conglobate acne, severe inflammatory acne, and severe acne breakouts associated with the initiation of isotretinoin treatment. In addition, oral corticosteroids can be used in patients with congenital adrenal hyperplasia to suppress adrenal production.  

Step 4: Procedural therapies   

Manual extraction of comedones, electrocauterisation of macrocomedones, intralesional infiltration with triamcinolone, and the draining of cysts and abscesses have been used in selected patients for the treatment of acne lesions.  

Laser and light therapy, as well as photodynamic therapy, have been used in the treatment of acne with varying success.  

Several modalities are helpful in the management of atrophic scars resulting from acne. Dermabrasion can help in treating superficial scars if conducted carefully. Deeper scars can be smoothed by dermal fillers such as hyaluronic acid, l-poly-lactic acid, polymethylmethacrylate, platelet-poor plasma gel, platelet-rich plasma, and autologous fibroblasts.  

Other treatment options include chemical peels, skin micro-needling, traditional non-fractional ablative laser resurfacing, ablative fractional laser resurfacing, non-ablative fractional laser resurfacing, dermaroller, radiofrequency, punch excision, punch lift/elevation, and subcision.  

Treatment for hypertrophic acne scars and keloids may be required for cosmetic purposes. Intralesional corticosteroid injections are the most effective and the first-line treatment for hypertrophic scars and keloids. If treatment with intralesional corticosteroid monotherapy is unsuccessful, one may consider multimodality therapy such as liquid nitrogen followed by intralesional steroids, followed by silicone gel sheeting, and/or pulsed-dye laser therapy.  

If these measures result in an insufficient response, surgical excision with preoperative, intraoperative, and postoperative corticosteroid injections as well as pressure dressing, if applicable, can be considered.  

Conclusion 

Acne vulgaris is a common, chronic, inflammatory disorder of the pilosebaceous unit that affects most adolescents with inflammatory lesions on the face and trunk and may progress to scars. The condition can lead to emotional stress and the impact on quality of life can be significant. Timely and proper treatment of acne may reduce the risk of scarring. Therefore, early, and effective treatment is extremely important.  

REFERENCES 

1.Leung AK, Barankin B, Lam JM, et al. Dermatology: how to manage acne vulgaris. Drugs in Context, 2021. 

2.Graber E. Patient education: Acne (Beyond the Basics).UpToDate, 2022. https://www.uptodate.com/contents/acne-beyond-the-basics 

3.Espinosa NI, Cohen PR. Acne Vulgaris: A Patient and Physician’s Experience. Dermatol Ther (Heidelb), 2020.  

4.Narang I, Sardana K, Rajpai R, et al. Seasonal aggravation of acne in summers and the effect of temperature and humidity in a study in a tropical setting. Journal of Cosmetic Dermatology, 2018. 

5.American Academy of Dermatology. Acne: tips for managing. https://www.aad.org/public/diseases/acne/skin-care/tips 

6.American Academy of Dermatology. What can clear severe acne? https://www.aad.org/public/diseases/acne/derm-treat/severe-acne