Acne Vulgaris, Folliculitis, and Acne Rosacea

Sonya K. Brown, M.D., and Alan R. Shalita, M.D.

Acne vulgaris, folliculitis, and acne rosacea are common disorders of the pilosebaceous units, which consist of sebaceous glands and their associated hair follicles. The most common anatomic sites of involvement are those that have the largest and greatest density of sebaceous glands: the face, neck, upper chest and back, and upper arms.

Acne Vulgaris

Acne vulgaris is a common disorder that peaks in incidence around the time of puberty. The pathogenesis of acne vulgaris is multifactorial. Abnormal keratinization in the upper canal of the hair follicle causes formation of hyperkeratotic, adherent plugs that are derived from desquamated epithelial cells, resulting in comedones (appearing clinically as whiteheads and blackheads), the noninflammatory lesions of acne vulgaris. Androgens stimulate the secretion of lipid-rich sebum from the sebaceous glands; sebum, in turn, provides a growth substrate for the commensal Propionibacterium acnes, an anaerobic diphtheroid. Proliferation of P. acnes is particularly facilitated by the anaerobic environment of the follicles that are plugged by comedones. This results in the production of proinflammatory mediators that are largely responsible for the appearance of the inflammatory lesions of acne vulgaris: papules, pustules, and nodules (Figure 1 and Figure 2).

Treatments for acne vulgaris target one or more of its pathogenetic factors. Topical agents alone might be used for mild cases of acne, whereas systemic agents are generally reserved for patients with moderate to severe involvement. Comedolytic agents act primarily against comedones and include tretinoin and adapalene, both of which are available only as topical preparations. For diminishing the growth of P. acnes, antibiotics and antibacterials are available in various topical and systemic preparations (Table 1) and are effective against the inflammatory lesions of acne vulgaris. Antiandrogens, administered orally, diminish sebum production, which results in the improvement of inflammatory lesions. Isotretinoin (13-cis-retinoic acid) is a potent systemic agent that affects all of the major pathogenetic factors of acne vulgaris. However, because it can cause a variety of adverse effects, some of which are potentially serious (Table 2), isotretinoin is generally reserved for the treatment of severe, treatment-resistant acne.

Folliculitis

Folliculitis is a somewhat nonspecific term that refers to inflammation of the hair follicle (in clinical practice, this term does not include acne vulgaris). The most common etiology of folliculitis is bacterial infection, often due to Staphylococcus aureus. The usual clinical presentation is superficial pustules and/or papules in the distribution of the hair follicles. The face, chest, back, thighs, and buttocks are often involved. Folliculitis is frequently initiated by mild physical injury to the follicles, such as friction caused by tight-fitting garments, or by ingrown hairs in the beard area in men. Less commonly, folliculitis is caused by infection by fungi, such as dermatophytes or Pityrosporum. Folliculitis due to Pseudomonas aeruginosa ("hot tub folliculitis") might occur in patients exposed to water sources that are contaminated by that organism. Treatment of folliculitis is aimed at eliminating the offending agent(s), and includes topical and/or systemic antibacterial or antifungal preparations.

Acne Rosacea

Rosacea is an inflammatory disorder of uncertain etiology that most commonly affects adults of northern European ancestry, between 30 and 50 years of age. The earliest manifestation of this disease can be recurrent episodes of flushing and blushing, often triggered by stimuli such as ingestion of hot beverages, spicy foods, and ethanol or exposure to ultraviolet radiation. Clinical findings in the fully developed eruption include papules, pustules, erythema, and telangiectasias. The central face, including the nose, forehead, chin and cheeks, is involved predominantly. Chronic inflammation might lead to permanent enlargement (phyma) of the affected areas due to sebaceous gland and soft tissue hypertrophy; rhinophyma ("W. C. Fields nose") refers to enlargement of the nose. Involvement of the eye might lead to conjunctivitis and/or blepharitis. Rosacea might clinically resemble acne vulgaris; however, in contrast to acne, comedones are absent. Treatments of mild rosacea include topical metronidazole gel, lotion or cream, or a combination of sodium sulfacetamide and sulfur. In moderate to severe cases, oral antibiotics, of which the tetracyclines are the most widely used, might be added. Isotretinoin might be used in severe, recalcitrant cases.

References

1. Rothman KF, Lucky AW. Acne vulgaris. Adv Dermatol 1993; 8: 347-74.
2. Brown SK and Shalita AR. Acne vulgaris. Lancet 1998; 351:1871-76.
3. Habif T. Bacterial infections. In: Clinical Dermatology. St. Louis: Mosby Co., 1996, pp. 248-58.
4. Wilkin JK. Rosacea: pathophysiology and treatment. Arch Dermatol 1994; 130: 359-62.
   

Figure Legends

Figure 1. Multiple closed comedones (whiteheads; A) and open comedones (blackheads; B) in two patients with papular and cystic acne vulgaris. Note the acne scarring in the second patient.

Figure 2. Post-inflammatory hyperpigmentation in a patient with papular and cystic acne.

 

Table 1. Antibacterial/antibiotic agents used in the treatment of acne vulgaris.

Topical
Benzoyl peroxide
Clindamycin
Erythromycin
Sodium sulfacetamide with or without sulfur

Systemic
Tetracycline
Doxycycline
Minocycline
Erythromycin
Trimethoprim/sulfamethoxazole

Table 2. Adverse effects of isotretinoin

Teratogenicity: craniofacial, cardiovascular, central nervous system, and thymic malformations

Mucocutaneous: cheilitis; photosensitivity; dryness of skin and mucous membranes

Gastrointestinal: nausea/vomiting; acute pancreatitis (due to hypertriglyceridemia)

Psychiatric: possible mood changes

Laboratory: hypertriglyceridemia; elevated liver function tests, increased muscle enzymes

Questions: Acne Vulgaris, Folliculitis, and Acne Rosacea

1. A 16-year-old African-American girl presents with numerous comedones on the face. Papules and pustules are absent. Appropriate initial treatment would be:

A) Adapalene
B) Tetracycline
C) Clearasil
D) Topical steroids
E) Oral isotretinoin

2. The same patient subsequently develops a moderate number of pustules on her face. The addition of what topical or oral medication should be considered in this case?

A) Adapalene
B) Tetracycline
C) Clearasil
D) Topical steroids
E) Oral isotretinoin

2a. Why would isotretinoin NOT be considered as first-line therapy in this case?

3. A 30-year-old Asian male presents with papules and pustules around the hair follicles on his legs. What is the most likely etiology?

A) Lubricating lotion
B) Staphylococcus aureus
C) Fungus infection
D) Hot oil treatment
E) Pseudomonas aeruginosa

3a. What is the most likely diagnosis in this case?

3b. What topical or oral medication should be prescribed?

4. A 45-year-old, Irish-American man presents with papules, pustules and diffuse erythema on his face. Comedones are absent. What is the most likely diagnosis?

A) Photosensitivity
B) Rosacea
C) Lupus erythematosous
D) Acne vulgaris
E) Contact dermatitis

4a. What topical or systemic medication could be prescribed?

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