Numerous acne classification systems have been developed; some are based on the type of lesions (ie, comedonal, papulopustular, nodulocystic), while others also consider the number of each type of lesion and areas affected.15 In 2002, the US Food and Drug Administration (FDA) defined the components of a Global Acne Severity Scale as having 6 grades (0-5), with 0 for normal skin and 5 representing a predominance of highly inflammatory lesions with a variable number of papules/pustules and nodulocystic lesions.16
The AAD’S classification system has only 3 grades—mild, moderate, and severe—and is one of the easiest to use:
- Mild cases have few to several papules and pustules, but no nodules
- Moderate cases have more papules and pustules, with a few nodules
- Severe cases have numerous papules, pustules, and nodules.5
CASE Ms. S is in obvious emotional distress, and her acne needs to be treated aggressively. Because of the emotional impact and the fact that she has lesions on several body parts, her case is classified as severe (and would be even if her face had only a few lesions).
Treatment: Prevention of new lesions is paramount
Preventing new formations is a key focus of acne therapy, and patients should be advised that it may take weeks for results to be seen. Nonetheless, aggressive treatment of inflammatory lesions is necessary to prevent scarring. Because most patients have both inflammatory and bacterial lesions, it is important to use combined therapies, including topical or oral antibiotics, to treat P acnes and inflammation (TABLE 2).13,17-23
TABLE 2
Acne classification helps guide treatment decisions13,17-23
| Treatment | Severity of acne | ||
|---|---|---|---|
| Mild | Moderate* | Severe* | |
| Dietary/lifestyle modifications (eg, reduce dairy intake, minimize use of cosmetics, reduce stress) PLUS benzoyl peroxide (2%-10%) PLUS retinoid (tretinoin, adapalene, or tazarotene) OR azelaic or salicylic acid | √ | √ | √ |
| Combined OCPs PLUS oral antibiotics OR topical antibiotics (for males and females who are not candidates for OCPs) | √ | √ | |
| Isotretinoin† | √ | ||
| Other therapies, as needed (eg, intralesional injections, chemical peels, or laser therapy)‡ | √ | √ | √ |
| *Treatments for moderate or severe acne are also appropriate for acne that extends to other parts of the body and/or does not respond to topical therapy. †Monitoring and counseling on adverse effects and teratogenic potential are required. ‡Should not be used concurrently or within 6-12 months of isotretinoin due to increased risk of keloid formation. OCPs, oral contraceptive pills. | |||
Topicals are the cornerstone of treatment
Retinoids and benzoyl peroxide topicals are the foundation of therapy for both comedonal and inflammatory acne,17 regardless of severity. Both are recommended by the AAD. But evidence suggests that only 55% of dermatologists and 10% of primary care providers recommend them.19,20
Retinoids inhibit microcomedone formation and regulate follicular keratinocytes, which have anti-inflammatory properties and help to prevent the formation of new lesions. Patients should be warned that topical retinoids can cause irritation, erythema, desquamation, pruritus, and burning. To reduce the adverse effects, advise patients to start retinoid therapy slowly, at a reduced frequency (eg, every other day or every third day) and shorter contact (washing it off after one to 4 hours for a week, then increasing the contact time). When it is clear that the medication is well tolerated, the frequency and amount can be increased. Use of the topical, as tolerated, should continue as long as the potential acne problem remains.
There are 3 retinoid formulations on the market—adapalene, tretinoin, and tazarotene—all of which have been shown to be effective. Adapalene is the least irritating and the most stable, and can be safely combined with benzoyl peroxide and topical antibiotics. If tretinoin and benzoyl peroxide are used concurrently, tretinoin should be applied at night and benzoyl peroxide during the day. To reduce the risk of inactivating the topical agents, advise patients not to use other skin products in conjunction with topical therapy.
Benzoyl peroxide, which is available as a cleanser, gel, or wash, affects keratinocyte dysmaturation, P acnes, and inflammation.11 The antibacterial activity is due to its oxidation. Benzoyl peroxide is available both OTC and by prescription, with concentrations ranging from 2% to 10%. Salicylic acid (2%-3%), a well-tolerated keratolytic agent, is often used with benzoyl peroxide, as well. Azelaic acid, sodium sulfacetamide, and dapsone are other topicals that have been found to be effective in treating acne.
Topical antibiotics, most commonly clindamycin 1% or sodium sulfacetamide, also affect both P acnes and inflammation,24 although the exact mechanism is unknown. Available in solution or as a gel or lotion, topical antibiotics can be combined with benzoyl peroxide. Use of topical erythromycin has declined in recent years because it has a higher rate of bacterial resistance.9,21