Acne vulgaris treatment : the current scenario.

Acne Vulgaris is one of the most common skin disorders which dermatologists have to treat. It mainly affect adolescent, though may present at any age. In recent years, due to better understanding of the pathogenesis of acne, new therapeutic modalities and various permutation and combinations have been designed. In topical agents; benzoyl peroxide, antibiotics, retinoids, etc are the mainstay of treatment; can be given in combinations. While systemic therapy includes oral antibiotics, hormonal therapy, and isotretinoin, depending upon the need of patients it has to be selected. Physical treatment in the form of lesion removal, photo-therapy is also helpful in few of them. Since various old and new topical and systemic agents are available to treat acne, it sometime confuse treating dermatologist. To overcome this, panel of physicians and researchers worked together as a global alliance and task force to improve outcomes in acne treatment. They have tried to give consensus recommendation for the treatment of acne. Successful management of acne needs careful selection of anti-acne agents according to clinical presentation and individual patient needs.

Introduction

Acne vulgaris is one of the commonest skin disorders which dermatologists have to treat, mainly affect adolescents, though it may present at any age. Acne by definition is multifactorial chronic inflammatory disease of pilosebaceous units.[1] Various clinical presentations include seborrhoea, comedones, erythematous papules and pustules, less frequently nodules, deep pustules or pseudocysts, and ultimate scarring in few of them. Acne has four main pathogenetic mechanism—increased sebum productions, follicular hyperkeratinization, Propionibacterium acne (P. acne) colonization, and the products of inflammation.[2-5]

In recent years, due to better understanding of the pathogenesis of acne, new therapeutic modalities are designed.[3] Availability of new treatment options to compliment the existing armamentarium should help to achieve the successful therapy of greater numbers of acne patients, ensure improved tolerability and fulfil patient expectations. Successful management of acne needs careful selection of anti-acne agents according to clinical presentation and individual patient needs.

The purpose of this article is to review the treatment options available with us in the present scenario.

Topical therapy

Topical therapy is useful in mild and moderate acne, as monotherapy, in combination and also as maintenance therapy.

A. Benzoyl peroxide

It is an effective topical agent since many years and is available in different formulations (washes, lotions, creams, and gels) and concentrations (2.5–10%).[46]

The stability is very dependent on its vehicle. Gels are generally more stable and active and water-based gel being less irritant is more preferred over creams and lotions.[78] Benzoyl peroxide is a broad spectrum bactericidal agent which is effective due to its oxidizing activity.[7]

The drug has an anti-inflammatory, keratolytic, and comedolytic activities, and is indicated in mild-to-moderate acne vulgaris. Clinicians must make a balance among desired concentration, the vehicle base, and the risk of adverse effects, as higher concentration is not always better and more efficacious.[9]

The main limitation of benzoyl peroxide is concentration dependent cutaneous irritation or dryness and bleaching of clothes, hair, and bed linen.[10] It can induce irritant dermatitis with symptoms of burning, erythema, peeling, and dryness.[11] This occurs within few days of therapy and mostly subsides with continued use.

B. Topical retinoids

Retinoids have been in use for more than 30 years. Topical retinoids target the microcomedo–precursor lesion of acne. There is now consensus that topical retinoid should be used as the first-line therapy, alone or in combination, for mild-to-moderate inflammatory acne and is also a preferred agent for maintenance therapy.

Its effectiveness is well documented, as it targets the abnormal follicular epithelial hyperproliferation, reduces follicular plugging and reduces microcomedones and both noninflammatory and inflammatory acne lesions.[12-14] Their biological effects are mediated through nuclear hormone receptors (retinoic acid receptor RAR and retinoids X receptor RXR with three subtypes α, β, and γ) and cytosolic binding proteins.[15] Retinoic acid metabolism blocking agents (RAMBAs) such as liarozole have been developed recently to overcome the emergence of all-trans-retinoic acid resistance.[16]

Tretinoin, adapalene, tazarotene, isotretinoin, metretinide, retinaldehyde, and β-retinoyl glucuronide are currently available topical retinoids.[17] The most studied topical retinoids for acne treatment worldwide are tretinoin and adapalene.[18] There is no consensus about relative efficacy of currently available topical retinoids (tretinoin, adapalene, tazarotene, and isotretinoin). The concentration and/or vehicle of any particular retinoid may impact tolerability.[19] Adapalene was generally better tolerated than all other retinoid with which it was compared.[2021] Tretinoin has recently become available in formulations with novel delivery systems which improves tolerability. One such product Retin-A Micro (0.1% gel) contains tretinoin trapped within porous copolymer microspheres. Avita, the tretinoin is incorporated within a polyoylprepolymer (PP-2). Each of the theses formulations releases tretinoin slowly within the follicle and onto the skin surface, which in turn reduces irritancy with the same efficacy.[22]

The main adverse effects with topical retinoid is primary irritant dermatitis, which can present as erythema, scaling, burning sensation and can vary depending on skin type, sensitivity, and formulations.

C. Topical antibiotics

Many topical antibiotics formulations are available, either alone or in combination. They inhibit the growth of P. acne and reduce inflammation. Topical antibiotics such as erythromycin and clindamycin are the most popular in the management of acne and available in a variety of vehicles and packaging.[23] Clindamycin and erythromycin were both effective against inflammatory acne in topical form in combination of 1–4% with or without the addition of zinc.[24-26] An addition of topical 2% zinc sulfate and nicotinamide was no different than placebo for the treatment of acne.[27-29] Topical clarithromycin, azithromycin, and nadifloxacin are available in India, but trials for their efficacy and safety are lacking.

Side effects though minor includes erythema, peeling, itching, dryness, and burning, pseudomembranous colitis which is rare, but has been reported with clindamycin.[30] A most important side effect of topical antibiotics is the development of bacterial resistance and cross resistance; therefore, it should not be used as monotherapy.

D. Other topical/new agents

Combination therapy: Benzoyl peroxide has the advantage to prevent and eliminate the development of P. acne resistance. Therefore it is being more preferred as combination therapy. Its efficacy and tolerability are enhanced when combined with topical erythromycin or clindamycin, confirmed on various trials.[631-34] Benzoyl peroxide can be combined with tretinoin and found to be superior to monotherapy. Both the molecules should not be applied simultaneously as benzoyl peroxide may oxidize tretinoin.[35] A combination of topical retinoid and topical antimicrobial is more effective in reducing both inflammatory and noninflammatory acne lesions than either agent used alone.[36] Topical clindamycin and benzoyl peroxide applied once daily and fixed clindamycin phosphate 1.2% and tretinoin 0.025% in aqueous-based gel formulation used once daily are both found to be effective treatment for acne. Addition of zinc acetate to clindamycin and erythromycin gel showed equivalent efficacy but probably reduces the development of microbial resistance.[37]

Salicylic acid: It has been used for many years in acne as a comedolytic agent, but is less potent than topical retinoid.[38]

Azelaic acid: It is available as 10–20% topical cream which has been shown to be effective in inflammatory and comedonal acne.[3940]

Lactic acid/Lactate lotion: It is found to be helpful in preventing and reduction of acne lesion counts.[41]

Tea tree oil 5%: Initial clinical response with this preparation is inevitably slower compared to other treatment modalities.[42]

Picolinic acid gel 10%: It is an intermediate metabolite of the amino acid, tryptophan. It has antiviral, antibacterial, and immunomodulatory properties. When applied twice daily for 12 weeks found to be effective in both type of acne lesions, but further trials are needed to confirm its safety and efficacy.[43]

Dapsone gel 5%: It is a sulfone with anti-inflammatory and antimicrobial properties. The trials have confirmed that topical dapsone gel 5% is effective and safe as monotherapy and in combination with other topical agents in mild-to-moderate acne vulgaris.[44]

Systemic Therapy

Systemic antibiotics

0Oral antibiotics are indicated in mainly moderate-to-severe inflammatory acne.[5] Tetracyclines and derivatives still remain the first choice. Macrolides, co-trimoxazole, and trimethoprim are other alternatives for acne.[45] The following agents should not be used in acne due to lack of efficacy and safety consideration such as cephalosporins, sulphonamide, and gyrase inhibitors.[4]

Tetracycline (500 mg–1 g/day), doxycycline (50–200 mg/day), minocycline (50–200 mg/day), lymecycline (150–300 mg/day), erythromycin (500 mg–1 g/day), co-trimoxazole, trimethoprim, and recently azithromycin (500 mg thrice weekly) are being used successfully in acne.[46-50] Minocycline and doxycycline are more effective than tetracycline and erythromycin.[4647] Recently, doxycycline in subantimicrobial dose (20 mg twice daily) and an extended-release minocycline tablet (1 mg/kg/day) were used and found to be effective, but further controlled trials are needed.[3751]

Gastrointestinal upset and vaginal candidiasis are most common side effects. Doxycycline can be associated with photosensitivity. Minocycline may produce pigment deposition in the skin, mucous membrane, and teeth. Autoimmune hepatitis, systemic lupus erythematosus-like syndrome, and serum sickness-like reactions occur rarely with minocycline.

Long-term therapy with oral antibiotic not only threat to resistant of P. acne, but also to coagulase negative staphylococci on the skin, Staphylococcus aureus in the nares, and streptococci in the oral cavity.[5253] There is a significant association between antibiotic used in acne and the incidence of upper respiratory tract infection.[54]

Optimizing antibiotic therapy: Research has demonstrated that problem of antibiotic-resistant P. acne is increasing, and it is most common with erythromycin. Therefore there is need to consider for antibiotic prescribing policies and to advocate the use of nonantibiotic preparations wherever possible.

Antibiotic monotherapy is to be avoided and it can be combined with topical retinoid or benzoyl peroxide as per need.

Wherever possible the duration of therapy should be limited. The usual minimum duration of therapy is 6–8 weeks but can be given up to 12–18 weeks and more.

It is advisable to use the same antibiotic if retreatment is necessary and use benzoyl peroxide for a minimum of 5–7 days between antibiotic courses to reduce resistant organism.

Concomitant use of oral and topical therapy with chemically dissimilar antibiotics is to be avoided.

Hormonal therapy

It may be needed in female patients with severe seborrhoea, clinically apparent androgenetic alopecia, seborrhoea/acne/hirsuitism/alopecia (SAHA) syndrome, late-onset acne (acne tarda), and with proven ovarian or adrenal hyperandrogenism.

The main approach of hormonal therapy in acne is to prevent the effects of androgens on the sebaceous gland and probably follicular keratinocytes as well. It is wiser to take consultation with gynecologist before starting therapy.

a) Oral contraceptives

Estrogen is commonly combined with progestin to avoid the risk of endometrial cancer. Anti-acne effect of oral contraceptive governed by decreasing level of circulatory androgens through inhibition of luteinizing hormones (LH) and follicle stimulating hormone (FSH).[5556] The currently FDA approved agents include norgestimate with ethinyl estradiol, and norethindrone acetate with ethinyl estradiol.

b) Spironolactone

They functions primarily as a steroidal androgen receptor blocker. It may cause hyperkalemia (when higher doses are prescribed or when there is cardiac or renal compromise), menstrual irregularities.[5758]

c) Cyproterone acetate

It is the first androgen receptor blocking agent to be well studied and found to effective in acne in females.[5960] Higher doses have been found to be more effective than lower dose. It is also combined (2 mg) with ethinyl estradiol (35 or 50 μg) as an oral contraceptive formulation to treat acne.

d) Flutamide

It is useful in acne when given in females with hirsuitism.[6061]

Oral isotretinoin

Oral retinoid is indicated in severe, moderate-to-severe acne or lesser degree of acne producing physical or psychological scarring, unresponsive to adequate conventional therapy.[6263] It is the only drug that affects all four pathogenic factors implicated in the etiology of acne.

Although there are many studies, but very large evidence-based study is lacking to confirm the dosing schedule. The approved dose is 0.5–2 mg/kg/day, which is usually given for 20 weeks.[64-66] Alternatively, lower dose can be used for longer period, with a total cumulative dose of 120 mg/kg.[65] New developments and future trends are low-dose long-term isotretinoin regimens and new isotretinoin formulations (micronized isotretinoin).[51]

Side effects include those of musculoskeletal, mucocutaneous, and ophthalmic systems, as well as headache, and central nervous system effects.[66] Most of the side effects are temporary and resolves after the drug is discontinued. Oral isotretinoin is a potent teratogen. Therefore women of child-bearing age require negative pregnancy test before treatment, strict contraceptive measures essential before, during and even 6 weeks posttherapy. Due to this, in United States, a new risk management programme (iPLEDGE) has been developed where all the patients receiving this drug have to register.[6768]

Physical Treatment

a) Comedones

Both open and closed comedones can be removed mechanically with comedone extractor and a fine needle or a pointed blade.[4] Preprocedure topical retinoid application makes the procedure easier. Gentle cautery and laser puncture of macrocomedones are also useful procedure.[69] The limitations of comedo extraction include incomplete extraction, refilling, and the risk of tissue damage.

b) Active deep inflammatory lesions

Aspiration of deep inflamed lesion may be needed in few cases which are followed by IL steroid injection in cysts and sinus tract.[470]

a) Visible light

They are indicated for mild-to-moderate inflammatory acne. In vitro and in vivo exposure of acne bacteria to 405–420 nm of ultraviolet free blue light results in the photo-destruction through the effect on the porphyrin produced naturally by P. acne.[71] Use of limited spectrum wavelength, such as blue light (peak at 415 nm), and mixed blue and red light (peak at 415 and 660 nm) have been found to be effective in reducing acne lesions after 4–12 weeks.[7273]

b) Photodynamic therapy

(with addition of δ-aminolevulinic acid) and pulsed dye laser (585 nm) were also effective in acne, but further trials are needed to confirm the same.[74-76]

Physical treatment of scars

Acne scar can be broadly divided into two groups, those involving tissue losses (Ice pick scar, Box scar, Rolling scar, and Follicular macular atrophy) and those involving tissue excess (hypertrophic scars or keloids). Currently available treatment for scars include simple excision, and suturing, either alone or combined with punch grafting and laser resurfacing, dermabrasion, various type of lasers, chemical peels, and fillers. For hypertrophic scars, treatment includes pressure therapy, IL corticosteroid, 5-fluorouracil and bleomycin injections, surgical excision, radiotherapy, laser therapy and cryotherapy.

All the procedures have their own merits and demerits; to be chosen carefully seeing the merit.[77-79]

Acne and diet

Dietary restriction has not been demonstrated to be benefit in the treatment of acne.[8081] The myth that diet affects acne is widespread, but previous studies are not supporting it. Of late, various authors again claiming that there is the definite role of diet in acne but to conclude that further controlled trials are needed.[82-84] It has been shown that the prevalence of acne is lower in rural, nonindustrialized societies than in modernized western populations may be due to lower glycemic index diet, claims one trial.[85] Although not currently recognized within our dermatology standard of care, but due to “consistent and good quality patient oriented evidence”, dietary management of acne appears to be accumulating.

The benefit of dietary management in the treatment of acne has been neither demonstrated nor disproved.[8586]

Conclusion

Various topical and systemic drugs are available to treat acne, which may sometimes confuse the treating dermatologist. To overcome this situation a panel of physicians and researchers worked together as a “Global Alliance” and “Task Force” to improve outcomes in acne treatment.[87-89] They have tried to give consensus recommendation for the treatment of acne, mostly evidence-based and inputs from various countries. Similar alliance has also been formed in India recently with their recommendations.[90]

Topical retinoid

It should be primary treatment for most forms of acne vulgaris.

To be applied to entire affected area.

Antimicrobial to be added for inflammatory lesions.

Essential part of maintenance therapy.

Combination therapy

It works better and clearing of lesion is faster.

Stop antibiotic if inflammatory lesion subsides.

If withdrawal is not possible, switch to benzoyl peroxide plus an antibiotic.

Topical retinoid can be continued to prevent remission.

Antibiotics

Oral and topical antibiotics not to be used as monotherapy to prevent bacterial resistance.

Helpful in moderate-to-severe acne.

Generally oral antibiotics are well tolerated, sometimes associated with severe adverse events.

Always use the same antibiotic if it was effective previously.

Doxycycline and minocyclines are more effective than tetracycline.

Do not use chemically dissimilar oral and topical antibiotic together.

It is an excellent choice in women requiring oral contraceptive (estrogen containing) for other reason and having moderate-to-severe acne with SAHA symptoms. Oral antiandrogen like spironolactone and cyproterone acetate can be useful in the treatment of acne.

It is approved in severe recalcitrant nodulocystic acne. It can also be used in moderate-to-severe acne vulgaris resistant to conventional therapy, frequently relapsing, with severe psychological and physical scarring due to acne. Pre-treatment counselling, patient selection, and monitoring are critical due to its side effects like teratogenicity, and adverse psychiatric events.