Dermatologic Disorders

Published on 16/06/2015 by admin

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CHAPTER 11 Dermatologic Disorders

I. Acne

Acne is an inflammatory disease of the sebaceous glands (oil-producing glands) and hair follicles of the skin. Acne is marked by the eruption of pimples or pustules, especially on the face, back, and chest. Typically, acne treatments take four to eight weeks for full results.

A. Conventional acne treatments are based on the concepts of:

1. Reducing sebum production
2. Speeding up skin cell turnover
3. Fighting bacterial infection (i.e., Propionibacterium acnes)

B. Over-the-counter (OTC) topical treatments may dry up the oil, reduce bacteria, and promote exfoliation.

1. Benzoyl peroxide (e.g., Clean and Clear, Persa-Gel, Oxy 10 Spot Treatment)

a) Also available in prescription preparations alone or in combination with sulfur or a topical antibiotic

2. Salicylic acid (e.g., Biore Blemish Bomb, Clearasil Stay Clear, Zone Control Clearstic).
3. Sulfur and/or resorcinol (e.g., Clearasil Adult Care)
NOTE: Common side effects for all topical retinoids include skin dryness, peeling, redness, photo sensitivity

C. Prescription topical retinoid products that are derived from vitamin A work by promoting cell turnover and preventing blockage of the hair follicle.

1. Tretinoin (Avita, Retin-A, Renova)
2. Adapalene (Differin)
3. Tazarotene (Tazorac)

D. Antibiotics

For moderate to severe acne (inflammatory or nodulocystic acne), prescription oral or topical antibiotics may be needed to reduce bacteria and fight inflammation. Antibiotics may be used for months or years to control acne and may be used alone or in combination with topical therapy. Antibiotics can also lessen the effectiveness of birth control pills by killing beneficial bacteria in the gastrointestinal tract that are responsible for hormone metabolism.

1. Erythromycin (Erygel, Emcin, Emgel, Akne-mycin, others)

a) Anti-inflammatory properties that help reduce redness in lesions, in addition to killing bacteria
b) Dose

(1) Varies with the type used
(2) Topical application (gel, solution, medicated pledget): Applied twice daily to affected area(s).
(3) If given systemically, initial dose 500 mg PO twice a day and taken with food; dosage reduced to 250–500 mg/day PO after several weeks once improvement is seen.

c) Side effects

(1) Stomach upset and nausea, but can be used in pregnant women

2. Clindamycin (Cleocin T, Clindagel, Clindaderm, Evoclin, others)

a) Widely prescribed as a topical antibiotic for acne, rarely used systemically for acne due to side-effect profile
b) Topical dose

1) Gel, solutions, or lotion: Applied twice daily to affected area(s)
2) Foam: Applied once daily to affected area(s)

c) Side effects

(1) Serious intestinal infection, pseudomembranous colitis, caused by the bacteria Clostridium difficile. This side effect has been reported rarely with topical clindamycin use.

3. Tetracycline

a) Most widely prescribed oral antibiotic for acne
b) Dose

(1) Initially, 500 mg PO twice a day until a significant decrease in acne lesions is seen; dose may then be decreased to 250–500 mg PO once a day.
(2) Tetracycline antibiotics must be taken on an empty stomach to be most effective.

c) Caution

(1) Not recommended for pregnant women or children younger than 9 years because tooth discoloration of the forming teeth is common in children. If all permanent teeth have erupted, tetracycline antibiotics may be a choice in select preteens.
(2) All tetracyclines may cause sun sensitivity.

d) Other tetracyclines used for acne include minocycline (Minocin, initially 50–100 mg PO twice daily, especially useful for pustular type acne) and doxycycline (Vibramycin, initially 50–100 mg PO twice daily).

4. Isotretinoin (Accutane, Claravis, Sotret)

a) Effective for scarring cystic acne or acne that does not respond to other treatments. It is reserved for the most severe forms of acne.
b) Side effects

(1) Severe mental disorders including depression and suicide
(2) Heart, brain, bone/muscle, gastrointestinal, cholesterol, hearing, vision, and liver problems
(3) Severe allergic reactions
(4) Teratogenic

c) Caution

(1) Close monitoring is essential to possibility of severe birth defects
(2) Contraindicated in women trying to become pregnant or during pregnancy
(3) Pharmacists must also provide a detailed warning brochure called a MedGuide from the United States Food and Drug Administration (FDA) to all patients prescribed isotretinoin. All prescribers, pharmacies, and patients must also register and participate in the iPledge risk-management program in order to prescribe, dispsense, or receive the drug.

E. Oral contraceptives (OC)

1. May exacerbate or improve acne depending on the progesterone component’s androgenic activity. Those with greater androgenic activity (levonorgestrel) tend to exacerbate acne, and those with less (norgestimate) or no (drospirenone) androgenic activity have been reported to improve acne in women.
2. Oral contraceptives increase the risk of thromboembolic events, especially in women older than 35 years who smoke. Remember ACHES acronym to remember thromboembolic warning signs: Abdominal pain, Chest pain, Headache or pain or changes in the eyes, severe pain or swelling in the legs or the thighs
3. Adverse effects include breast enlargement and tenderness, GI upset, irregular vaginal bleeding, especially during the first 3 months of therapy.
4. Examples of OC brands that are FDA approved for the treatment of acne (acne dosage is the same as for the OC regimen):

a) Ethinyl estradiol; Drospirenone (Yaz)
b) Ethinyl estradiol; Norethindrone acetate (Estrostep)
c) Ethinyl estradiol; Norgestimate (Ortho Tri-Cyclen)

II. Alopecia

A. Alopecia areata: an autoimmune disorder in which the body’s immune system attacks hair follicles, resulting in unpredictable patches of hair loss on the scalp, face, and other parts of the body.

1. Treatment

a) Corticosteroids: betamethasone (Celestone), monthly injections into the scalp
b) Corticosteroid pills
c) Corticosteroid creams and ointments, such as betamethasone (Diprolene), have been applied to affected areas of the skin. However, creams and ointments are generally less effective than injections.

B. Androgenic alopecia: an inherited form of baldness. Unlike men, women rarely develop complete baldness. Women usually experience hair thinning only.

1. Treatment

a) Minoxidil (Rogaine)

(1) Available OTC. Applied directly to the area of hair loss at least two times a day for at least 4 months. The medication usually does not take effect until 4 months to 1 year.
(2) Mechanism of action

(a) Enlarges hair follicles

(3) Caution

(a) Patients who discontinue use of minoxidil will likely lose the hair that they have already grown.

b) Finasteride (Propecia)

(1) Only works in men. This pill must be taken daily to regrow hair.
(2) Dose

(a) 1 mg PO once daily

(3) Mechanism of action

(a) Inhibits high levels of dihydrotestosterone (DHT) around hair follicles. High amounts of DHT cause hair follicles to shrink, and hair falls out as a result.

(4) Caution

(a) Pregnant women and women hoping to become pregnant should avoid contact (including topical contact) with finasteride due to the risk of genital abnormalities to a male fetus.

c) Spironolactone (Aldactone)

(1) Originally marketed as a diuretic (water pill) for patients suffering from congestive heart failure. Women now take the drug off-label because its antiandrogen properties may stop and sometimes reverse hair loss. It may also be more effective in postmenopausal women and may be taken with a hormone replacement pill.
(2) It is taken initially at a low dosage (25 mg) once or twice daily. Incremental dosage increases may be used, if needed.
(3) This medication may take many months to show results in women.

d) Cimetidine (Tagamet)

(1) Initially used as a prescription drug to treat heartburn and stomach ulcers. Recently, this medication became available OTC.
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