02. Acne

Resident Editor: Michelle Matzko MD,PhD, M.D.

Faculty Editor: Ryan Arakaki, M.D.

BOTTOM LINE

✔ Categorize acne as comedonal, papulopustular, and nodulocystic to guide treatment.

✔ Treatment with isotretinoin requires in-depth counseling, registration into the I-Pledge database, and regular labs.

Background

  • Acne is a multifactorial disease of the pilosebaceous unit
  • Occurs in areas with a high concentration of sebaceous glands: face, neck, chest, back
  • Early comedo (small plug):
    • Skin cells turn over in hair follicle and are trapped by produced sebum (androgen stimulated)
  • Later comedo:
    • Trapped keratin and sebum accumulates
  • Inflammatory papule/pustule:
    • Cutibacterium acnes (formerly Propionibacterium acnes) proliferates resulting in mild perifollicular inflammation
  • Nodule/cyst:
    • Follicles rupture leaking trapped keratin, sebum, and bacteria
    • Results in severe inflammation and scarring

Signs and Symptoms

  • Divide into inflammatory versus noninflammatory (this helps to guide management)
  • Non-inflammatory acne (lesions not typically red or painful):
    • Closed comedones (whiteheads): Small white or skin-colored papules with no follicular opening
    • Open comedones (blackheads): Small skin-colored papules with dilated follicular outlet filled with oxidized keratin
  • Inflammatory acne:
    • Papulopustular: Erythematous papules and pustules
    • Nodulocystic: Larger, tender erythematous nodules and deeper cysts. Severe lesions can lead to scarring and sinus tract formation.

 

  • If a patient is well beyond puberty, has new acne, or is a hirsute woman, consider further evaluation for the following ddx:
    • Hyperandrogenic states (e.g. PCOS, ovarian or adrenal tumor)
    • Topical acnegenic agents (e.g. oils, creams, cosmetics, occupational exposures)
    • Excess hormones (e.g. OCPs, steroids, Cushing's)
  • Other conditions can mimic acne, but lack comedones
  • Differential Diagnosis of Acne
    • Bacterial folliculitis: Abrupt eruption; spread by scratching or shaving; variable distribution
    • Drug-induced acne: Use of androgens, ACTH, corticosteroids, cyclosporine, azathioprine, oral contraceptives, iodides, isoniazid, lithium, phenytoin
    • Hidradenitis suppurativa: Double comedo; starts as a painful boil; sinus tracts; intertriginous areas affected
    • Keratosis pilaris: Common condition with small follicular papules on extensor surfaces of upper arms and thighs; may have erythema
    • Miliaria: “Heat rash” in response to exertion or heat exposure; nonfollicular papules, pustules, and vesicles
    • Perioral dermatitis: Small grouped erythematous papules and pustules confined to the chin and nasolabial folds; clear zone around the vermilion border
    • Pseudofolliculitis barbae: Papules, pustules in beard area; affects curly-haired persons who regularly shave closely; may heal with keloid scars
    • Rosacea: Central facial erythema and telangiectasias; may have papules, pustules; no comedones
    • Seborrheic dermatitis: Greasy scales and yellow-red coalescing macules or papules eyebrows, nasolabial fold, hair-bearing areas of the scalp, face

 

Table 2: Specific Treatments for Acne

  • The goal is prevention; therefore, treat the entire affected area rather than spot treatment
  • Try all treatments for at least 3 months before calling “treatment failure”
  • No specific dietary recommendations; limited evidence high glycemic foods and some dairy may be associated

Comedonal acne (non-inflammatory)- Either topical retinoids or benzoyl peroxide can be used alone or in combination

Topical retinoids

 

- Target follicular hyperproliferation, desquamation, inflammation

- e.g. tretinoin (Retin-A®) or adapalene (Differin®, this is now OTC)

- Mainstay initial therapy for comedonal acne

- Counsel patients on usage and side effects

- Use: Apply pea-sized amount only at nighttime on the entire and completely dry face (no spot treating)

- Start by using 1-2x/week and increase over 2-3 weeks to daily as tolerated

- Side effects: extreme skin dryness and photosensitivity

Benzoyl peroxide

(2.5-10%)

- Targets C. acnes proliferation

- Unique in that it does not induce bacterial resistance

- Use: Start with the weakest strength, apply in am, allow 4-6 weeks for the skin to adjust before increasing PRN

- Note: Inactivates topical tretinoin, should not be applied simultaneously (BP in AM, retinoid at night)

- Side effects: Bleaches clothing and sheets

Papulopustular acne (mild-moderate inflammatory)

  • MILD first-line: Start with the above therapies (mono or combined) or other topical combination therapy: BP+topical abx, or BP+topical retinoid+topical abx.
  • Alternative therapies: switch topical retinoid or trial topical dapsone.
  • MODERATE first-line: treatment for mild acne as above OR add oral antibiotic (in conjunction with or as a replacement for a topical antibiotic)
  • Alternative therapies: Switch topical combination therapy OR change oral abx OR add OCP/spironolactone in females OR consider oral isotretinoin

Topical retinoids

See above; can first trial above combo of topical retinoids and BP in most cases, then step up treatment (particularly with moderate acne) to include the addition of topical antibiotic or oral antibiotic

Benzoyl peroxide

See above- should be continued with oral and topical abx to prevent resistance; combination BP+abx products available for Rx

Topical antibiotics

 

- Targets C. acnes proliferation

- Clindamycin 1% or erythromycin 2%; should be used with BP

- Available in solution (most drying), gel, or cream (least drying)

- Use: Start with 1-2x/week and increase gradually to daily as tolerated

- Dapsone is a newer FDA approved agent, works by inhibiting inflammation (expensive, no generic; use if fails above abx)

Oral antibiotics

- Target C. acnes proliferation; as above, use with BP

- Doxycycline has the fewest side effects (other antibiotics include minocycline, tetracycline, erythromycin, TMP/SMX)

- Antibiotics work through their anti-inflammatory effects, not through their antimicrobial properties

- Does not start to see improvement until at least 6 weeks

- Discontinue when desired goals met and continue benzoyl peroxide and topical retinoid for maintenance

Oral contraceptives

(female)

- Targets sebum production: All OCPs may theoretically help by lowering free testosterone levels, but some can worsen acne in select patients

- OCPs containing norgestimate and desogestrel are the least androgenic (e.g., Desogen®, Ortho-Cept®, Ortho-Tricyclen®, Brevicon®, Demulen®).

- Progestogen-only contraceptives can worsen acne

Nodulocystic acne (severe inflammatory)

  • SEVERE first-line: Oral abx+topical combination therapy OR oral isotretinoin

Oral isotretinoin (Accutane)

- Also useful for treatment-resistant acne

- 0.5-1.0 mg/kg/day (usually 1mg/kg/day) x 16-20 weeks

- Cumulative dose 120-150 mg/kg

- For very severe acne, start at low doses (0.25 mg/kg/day) to avoid triggering acne fulminans

- I-Pledge: mandatory registry for all prescribing physicians, dispensing pharmacists, and patients

- Side effects: teratogenicity (counsel on birth control), GI upset, hypertriglyceridemia, transaminitis, myalgias/arthralgias, night blindness, photosensitivity, excessive skin/mucous membrane dryness

- Lab monitoring: Lipid panel, CBC, LFTs, pregnancy test before starting then monthly before receiving prescription

 

References

Titus S, Hodge J. Diagnosis and treatment of acne. Am Fam Physician. 2012 Oct 15;86(8):734-40.

Thompson AE. Acne. JAMA 2015 Feb 10; 313(6): 639-640.

Williams HC, Dellavalle RP, Garner S. Acne vulgaris. Lancet. 2012 Jan 28;379(9813):361-72.

 

Zaenglein AL, Pathy AL, Schlosser BJ, et al. Guidelines of care for the management of acne vulgaris. J Am Acad Dermatol 2016: 74:945.