In order to maximize results and minimize complications in the treatment of acne vulgaris, it is imperative to first decide which treatment is best for the individual sufferer and also the exact treatment method to be followed.

Different Groups of Retinoids

Among the many methods and medicines widely available, topical retinoid preparations are best used for treating mild forms of non inflammatory acne characterized by the presence of comedones. Topical retinoids can also be used together with systemic drugs to treat moderate to severe forms of acne as well.

Retinoids are derived from Vitamin A. They were first observed to be extremely effective in curing acne in the 1970’s. There are at present 3 generations of retinoids classified into nonaromatics, including retinol, tretinoin and isotretinoin; monoaromatic retinoids and polyaromatic retinoids, which include arotinoid, adapalene and tazatorene. These third generation retinoids have anti inflammatory efficacy. Topical retinoids popularly used in effectively treating acne are tretinoin, isotretinoin, adapalane, tazarotene and retinaldehyde.

The Function of Topical Retinoids

The aim of acne therapy is to decrease and minimize the incidence as well as the severity of the basic clinical lesion known as the microcomedo. If left untreated, a microcomedo may progress to other severe forms of acne. Retinoids have the capacity to bind, as well as activate, retinoid receptors on cells. By exerting their influence on cells via these receptors, retinoids help eliminate the formation of comedones by normalizing the cell differentiation in the follicles of the epithelial layer. Retinoids are considered to be both vitamins as well as hormones due to their binding as well as activation properties. The topical retinoid treatment should not only be restricted to application on visible lesions, but the entire acne prone area should be targeted to help prevent future spots.

Tretinoin

Tretinoin is the generic name for retinoic acid and is a first generation nonaromatic topical retinoid also known as Vitamin A acid. Tretinoin has a high affinity in binding all nuclear hormone retinoic acid receptors and cellular retinoic acid binding receptors.

Tretinoin is available in cream, gel and solution forms. It is effective in increasing the formation of follicular epithelial cells and facilitating the elimination of corneocytes thus enabling normalization of keratinization and drainage of comedones as well as preventing the formation of new comedones. The follicles become clear and aerobic and more within the reach of antimicrobial agents. This function inhibits the P. acnes bacteria proliferation and their proinflammatory activity on the follicles.

The patients should be told of the epidermal irritation and pustular flare side effects, plus the delayed and erratic improvement that may occur after application. Also, tretinoin usage may cause photosensitization. Night time application starting with a lower potency is advised. Patients with sensitive skin should avoid tretinoin and instead use another retinoid which causes less discomfort. However, nowadays two new formulations of tretinoin, namely the polyolpolymer-2 and the microsponge delivery system, are used for lower accompanying irritation.

Isotretinoin

This is a first generation retinoid which also has the capacity to bind CBRAR and RAR receptors. It has comedolytic properties thereby changing the turnover of epithelial cells in hair follicles. Topical isotretinoin is available in gel formula with .05 % potency. Oral isotretinoin is a sebum suppressor but the gel form does not have this quality. Its effect in reducing both comedolytic as well as inflammatory acne is almost equal to tretinoin. However, the adverse irritation effects which occur with tretinoin do not occur so frequently and as intensely with isotretinoin.

Adapalene

This is a third generation polyaromatic retinoid. Adapalene has some of the characreristics of tretinoin but it is different physiolochemically. It normalizes cellular keratinization and inflammation, thus it is extremely comedolytic as well as anti inflammatory. Though as effective as tretinoin, it is much better tolerated and produces less skin irritation and erythema. Also Adapalene is stable with oxygen and light so it can be applied at any time of the day and it can be combined with benzoyl proxide. There is negligible absorption of adapalene and once it goes into the corneum strata, it becomes enclosed in the targeted area of the epidermis and hail follicle. Adalapene has enormous potential as a topical therapy in acne.

Tazarotene

It has been seen that tazarotene when applied once a day has greater success in treating non inflammatory acne and reducing its severity compared to tretinoin. Also tazarotene gel .05% is more effective in lessening the number of open comedones and papules and reducing pustules faster than the same potency of tretinoin gel. However, it is as equally intolerable as tretinoin. Moderate skin irritation accompanied by burning and itching sensations, erythema, peeling and dryness is felt by some patients. So it is advised that tazarotene be applied for a very short period of time of 30 seconds to 5 minutes everyday for optimum results, but with a lower irritation level.

Retinaldehyde

This topical retinoid with .05% potency has an effect similar to that of tretinoin .025%. It has a comedolytic effect and directly prevents the proliferation of P.acnes. Retinaldehyde has much better tolerability and can be a better option compared to other retinoids.