Acne vulgaris is a chronic inflammatory condition of the cutaneous pilosebaceous unit. It is among the most common dermatologic complaints, affecting approximately 9% of the world’s population,1 and it has been recognized as a treatable condition since the time of the ancient Greek physicians Aristotle and Hippocrates.2 The phrase “acne vulgaris” is likely derived from the ancient Egyptian term aku-t, which means boil, pustule, or inflamed swelling, and vulgaris, meaning common in Latin.2,3
Factors such as bacterial colonization by Propionibacterium acnes, hormone-related sebum production, aberrant keratinization, and local inflammatory response play a role in the pathogenesis of acne, although how these factors interact is incompletely understood.4,5 The microcomedone, the precursor lesion in acne, forms from follicle obstruction due to dysfunction in epithelial desquamation. Excessive androgen-induced sebum production creates a favorable anaerobic environment for P acnes to flourish, resulting in an inflammatory reaction and keratinocyte proliferation.6
Acne can present as comedones, papules, nodules, and/or cysts. Although acne can affect individuals of all ages, prevalence is highest during puberty, with as many as 80% to 95% of adolescents affected. Facial scarring due to acne occurs in approximately 20% of teenagers, and perseverance of acne into adulthood is not uncommon.4,7 Acne affects both genders equally.8
Clinical manifestations of acne can range from mild to severe and most commonly affect the face, back, and chest, where sebaceous glands are most concentrated. Family history, supported by twin studies, and environmental factors, such as climate and pollution exposure, have been shown to contribute to the development of acne, but the relation of diet and smoking with acne is less clear.7 Several studies have linked intake of refined carbohydrates and certain dairy products to acne.9,10
A diagnosis of acne is made by identifying the characteristic lesions on physical examination, with further classification based on type and severity of lesions. Comedomal acne is noninflammatory and contains dilated follicles with keratin, sebum, and bacteria. Whiteheads are closed comedomes, while blackheads are open comedomes filled with debris. Papulopustular acne is a type of inflammatory acne characterized by pustules containing a center of purulent material and pink or red papules measuring 2 mm to 5 mm in diameter. Nodular acne involves raised inflammatory lesions measuring >5 mm in diameter. Acne can be described as mild, with less than 30 total lesions; moderate, with 30 to 125 lesions; and severe, with more than 125 lesions or more than 5 nodules.11 Histologically, acne is defined by the dilation of normal sebaceous glands, forming comedomes. Perifollicular inflammatory infiltrate, excess keratin, and the presence of P acnes may also be noted.4
Other dermatologic lesions may resemble acne but do not present with comedomes. Differential diagnosis includes keratosis pilaris, milia, rosacea, periorificial dermatitis, molluscum contagiosum, flat warts, tuberous sclerosis, pseudofolliculitis barbae, and medication reaction. A thorough history and physical examination, including medication review, are important for reaching the correct diagnosis. Aggravating and relieving factors and family history may be helpful during evaluation. Acne in young children may warrant an endocrinology workup.11
The goals of treating acne are to prevent future outbreaks, resolve existing lesions, and limit scarring. Depending on the severity of lesions, comorbid conditions, patient preferences, and goals of care, a variety of medications can be used. Targets of acne medication include hormonal, antibacterial, sebum production, and keratinization.
Topical retinoids are vitamin A derivatives that reduce follicular occlusion by regulating keratinization, thereby decreasing acne-related hyperpigmentation and scarring. As topical retinoids increase sun sensitivity, they should be used along with sunscreen. Topical antimicrobials such as benzoyl peroxide, erythromycin, and clindamycin target P acnes, thereby reducing associated inflammation.
Oral antibiotics are used in more severe cases of inflammatory acne or when the chest and/or back are affected. Macrolides and tetracyclines are often used for oral treatment but are not intended for long-term use. Minocycline is preferred over tetracycline by many providers due to its speedier resolution of inflammatory acne.12 Oral isotretinoin is used for severe cases of acne and has been shown to induce apoptosis in sebaceous glands. Women undergoing treatment with oral isotretinoin must use an effective method of birth control due to the teratogenic nature of this medication, and liver enzymes and lipids must be monitored in all patients.11 Other common side effects of treatment with oral isotretinoin include dry skin and lips.13
For comedomal acne, treatment with topical retinoids, salicylic acid, or azelaic acid represent a suitable first step. The addition of a topical antimicrobial agent may help in individuals with mild pustular or papular types. Individuals with moderate papular or pustular acne may benefit from oral antibiotics, topical retinoids, and benzoyl peroxide. For those with nodular or severe acne, oral isotretinoin may be considered. Women with moderate to severe acne may consider antiandrogen therapy, and oral contraceptives may be beneficial if the timing of acne outbreaks coincides with menses.11
Although acne is not a life-threatening condition, morbidity from acne can have a significant psychological impact, especially in the adolescent population. The peak of acne prevalence coincides with major physical, social, and emotional development in these patients, magnifying the psychosocial effects of even mild cases of acne. Patients with acne have higher rates of depression and suicidal ideation and lower rates of pride and self-worth.14 Timely and appropriate treatment, therefore, can limit this psychosocial impairment in the short term by limiting acute lesions and in the long term by preventing scar formation.
The patient presented in this case was given topical retinoids and oral doxycycline. The patient started to see resolution of her acne within 2 to 3 weeks and has been maintained on only a topical retinoid.
Click to the next page for Case 2.