Acne affects young adults commonly. There is no universal classification to label the lesions moderate or severe. However, severe acne may have some of the following features:

• Extensive lesions
• Acne with nodules and cystic lesions
• Presence of scarring
• Presence of draining lesions and sinuses
• Lack of response to therapy.

  ---

Pretreatment assessment of moderate and severe acne:

Prior to initiating therapy, the patient should be assessed for the following:

• Clinical type and severity of acne
• Skin type
• Presence or absence of acne scarring
• Presence of postinflammatory hyperpigmentation
• Features of hyperandrogenism
• Psychologic impact of acne on the patient
• Prior therapy
• Use of cosmetics that promote acne

• ---

Medical therapies for acne target one of the following mechanisms:

• Follicular hyper proliferation
• Abnormal desquamation
• Increased sebum production
• Bacterial proliferation, and
• Inflammation

The following groups of medicines are used to treat moderate and severe acne:

1. Bacterial proliferation:

   • Benzoyl peroxide
   • Azelaic acid
   • Topical and oral antibiotics

2. Drugs that target follicular hyperproliferation and abnormal desquamation

   • Salicylic acid
   • Hormonal therapies
   • Topical and oral vitamin A derivatives (retinoids)
   • Azelaic acid

3. Inflammation:

   • Isotretinoin
   • Oral tetracyclines
   • Azelaic acid

4. Increased sebum production:

   • Hormonal therapies
   • Oral vitamin A derivatives (isotretinoin)

5.  

   ---

Treatment and selection of therapy require the following principles to be incorporated into the treatment regimen:

• Both comedonal or non-inflammatory acne and inflammatory acne can be treated with topical retinoids. The majority of acne patients need topical retinoids.

Topical retinoids normalize skin hyperkeratosis and thus prevent the formation of micro-comedones. Patients with comedonal acne may be treated with topical retinoids as monotherapy.

• Patients may require antimicrobial therapy like benzoyl peroxide or topical antibiotics if there is inflammation.

  ---

• Patients may require oral antibiotics like oral tetracyclines if there is severe inflammation.

  ---

• To reduce the emergence of antibiotics resistance, topical benzoyl peroxide is used often

  ---

• If there is indications of a hyperandrogenic state in the patient, hormonal therapy may be necessary.

  ---

• Patients should be counselled regarding the optimal duration of therapy. At least two to three months of therapy are required before concluding that the therapy is ineffective.

  ---

• Maintenance therapy may require an even longer duration to prevent a recurrence.

Treatment approach according to the patient’s condition:

• Moderate papulopustular and mixed acne:

  • Topical retinoid combined with oral antibiotics and topical benzoyl peroxide
•  

• Comedonal ( noninflammatory acne):

  • Topical retinoids are used to treat (alternative therapies include salicylic acid and azelaic acid)

• Severe acne (nodular acne)

  1. Topical retinoids, oral antibiotics, and topical benzoyl peroxide, or
  2. Oral isotretinoin monotherapy

• Mild papulopustular and mixed comedonal & papulopustular acne:

  • Treat with a topical antimicrobial and topical retinoid

•  

  ---

A sample regimen of a patient who is being treated for mild inflammatory facial acne:

In the morning:

• • Use a light facial cleanser to wash your face.
  • Apply a thin coating of topical clindamycin/benzoyl peroxide gel with a predetermined dose to the face.

At night:

• • Use a light facial cleanser to wash your face.
    Apply a topical retinoid in a thin layer over the entire face.

    ---

Patients with oily skin may prefer certain gels because of their drying properties. Foams may be easily applied to hair-bearing areas while a solution can be easily spread over the entire face.

Topical retinoids for most patients:

Topical retinoids are the mainstay of therapy in most patients for the treatment of both inflammatory and non-inflammatory acne.

With the exception of topical adapalene 0.1% gel, which may be acquired over-the-counter, most topical vitamin A derivatives require a prescription from a doctor.

Retinoids, apart from the effects on comedones formation, also improve inflammation.

It also accelerates the resolution of acne-induced post-inflammatory hyperpigmentation. Topical retinoids may be used for maintenance and may diminish the long-term use of antibiotics.

How to use topical vitamin A derivatives:

Topical vitamin-A derivatives include:

1. 1. Topical tretinoin
   2. Isotretinoin
   3. Adapalene
   4. Tazarotene

One time per day, topical retinoids are used, ideally at night because they are photolabile. Adapalene is more light stable. Topical tretinoin is less stable when used in combination the same time as benzoyl peroxide. In the presence of benzoyl peroxide, adapalene, tretinoin gel microsphere and micronized versions, and tazarotene all maintain greater stability than tretinoin. Combination products are also available. Patients should apply a thin layer over the entire face. This may be done by applying a pea-sized amount of medicine. Individual acne lesions should not be treated. Patients may experience skin irritation which can be minimized by starting with the lowest potency and gradually increasing the dose. Adapalene 0.1% produces less irritation than other formulations. Tazarotene is considered the most effective but the most irritating as well. This side effect may be minimized by applying the medicine and washing it after five minutes.

Other adverse effects of topical retinoids include:

Skin flaking and dryness are common during the first month after starting treatment.

Other irritating topical agents, such as abrasive soaps, toners, astringents, and salicylic acids, should be discouraged from use on patients.

On top of a retinoid, a noncomedogenic moisturiser may be used.

Photosensitivity has been noted with the use of retinoids. Sun-protective clothing or sunscreens should be used if symptoms of photosensitivity are a problem.

Topical retinoids should not be used during pregnancy. Particularly for pregnant women, category X drugs include tazarotene.

Topical antibiotics for acne:

Among the topical antibiotics and antimicrobials used to treat acne are:

1. 1. Macrolides including erythromycin and azithromycin
   2. Benzoyl peroxide
   3. Clindamycin

Topical retinoid and topical antibacterial combination therapy is superior than monotherapy with either drug alone.

Benzoyl peroxide is also comedolytic. It is available on prescription and as over-the-counter preparation (2.5%)  medicine.

Patients using a higher dose of benzoyl peroxide may experience more irritation, dryness, stinging, tightening, erythema and burning sensation.

Topical acne treatments using salicylic acid and/or benzoyl peroxide might cause patients to experience potentially fatal adverse reactions.

Benzoyl peroxide may reduce the chances of developing antibiotic resistance in patients on long-term treatment.

Benzoyl peroxide should not be used simultaneously with retinoids. If both the agents are prescribed, the timing must be changed.

Clindamycin and erythromycin are two of the most often used topical medications for the treatment of acne.

For greater efficacy, topical retinoids should be administered in conjunction with these topical antimicrobials rather than as a monotherapy.

Sulfacetamide and dapsone are other options but should not be used in patients with sulfa allergy.

Azelaic acid contains comedolytic, mild anti-inflammatory, and antibacterial effects. In terms of effectiveness for the treatment of mild to moderate acne, it is comparable to topical 2% erythromycin, 5% benzoyl peroxide gel, and 0.05% tretinoin cream.

Topical salicylic acid may be used in patients who can not tolerate topical retinoids.

Oral antibiotics for moderate and severe acne:

Tetracycline derivatives like doxycycline and minocycline are the preferred and commonly used oral antibiotics because of their better efficacy and tolerability.

Minocycline was the preferred antibiotic in the past, however, doxycycline has similar efficacy and is less toxic. It is, therefore, considered first-line therapy. Minocycline may be tried in patients who have a poor response to doxycycline.

Tetracyclin and its derivatives doxycycline and minocycline should not be used in children and pregnant women.

It might impede bone development and cause permanent tooth discoloration. GI distress, esophagitis, esophageal ulceration, and idiopathic intracranial hypertension are other side effects of these medicines.

Also possible is photosensitivity. Minocycline is the least photosensitive of the tetracyclines.

Antiandrogens may be given to patients who have evidence of hyperandrogenism.

Oral isotretinoin is effective for the treatment of acne that is more severe, recalcitrant, and nodular acne. It may also be used in patients with acne associated with significant scarring.

In Conclusion:

A combination of medications, including Vitamin A derivatives, antimicrobials, antiseptics, and hormone therapy, is needed to treat moderate to severe acne.