Acne Vulgaris (Pimples)


Acne Vulgaris is one of the most common skin diseases.

It is a disorder of the pilosebaceous follicles. It typically first appears during puberty when androgenic stimulation triggers excessive production of sebum.

Many factors interact to produce acne in a given patient.

These include:

  • Genetics
  • Sebum production
  • Hormones
  • Bacteria
  • Properties of the sebaceous follicle
  • Immunologic

Over-production of stratum corneum cells (hyperkeratosis) obstructs the hair follicles at the follicular mouth producing open comedones, or blackheads.

Just beneath the follicular opening in the neck of the sebaceous follicle it causes microcomedones (closed comedones, or whiteheads).

There is an overgrowth of gram-positive
bacteria in the obstructed follicle:

  • Propionibacterium acnesor
  • Staphylococcus epidermidis;
  • distally Pityrosporum ovale

Rupture of the comedonal contents into the dermis induces a foreign body reaction and inflammation.

Symptoms and clinical features of Acne Vulgaris (Pimples)

Almost every individual has some degree of acne during puberty, with spontaneous resolution occurring in early adult life.

Occasionally, the disease persists into the
fourth decade, or even remains a life-long problem.

Favoured sites are the face, upper back and upper chest and shoulders. There may be mild soreness, pain, or itching.

It may present differently in different age groups.

  • Pre-teens often present with comedones as their first lesions
  • Teenage acne is invariably inflammatory and the lesions include firm red papules,
    pustules, abscesses, indurated nodules, cysts and rarely interconnecting draining
    sinus tracts

Inflammatory acne can be classified as mild, moderate, or severe

Mild acne:

  • Few-to-several inflammatory papules and pustules, but no nodules

Moderate acne:

  • Several-to-many papules, pustules, and a few to several nodules

Severe acne (acne conglobata):

  • Numerous fistulated comedones;
    extensive inflammatory papules;
    pustules; many cysts, abscesses, nodules, and draining sinuses
  • The lesions may be generalized, involving even the buttocks
  • Excoriation of acne papules and. microcomedones are common, and scarring may result
  • Usually, multiple shallow erosions or crusts are found

Differential diagnoses

  • Acne rosacea
  • Dermatosis papulosa nigra
  • Steatocystoma multiplex
  • Syringoma
  • Trichoepithelioma
  • Warts
  • Angiofibromas of tuberous sclerosis
  • Molluscum contagiosum
  • Steroid acne from the use of systemic steroids or topical fluorinated steroids on the face (often as cosmetic skin lightening creams)
  • Some drugs may produce acneiform eruptions
    • Androgens
    • Adrenocorticotropic hormone (ACTH)
    • Glucocorticoids
    • Hydantoins
    • Isoniazid
    • Halogens

Complications of Acne Vulgaris (Pimples)

  1. Psychosocial problems from cosmetic disfigurement
  2. Post-inflammatory pigmentary changes
  3. Pitted scars Keloids
  4. Acne fulminans (acute febrile ulcerative acne conglobata with polyarthritis and leukemoid reaction)


  • Usually, none required
  • In the presence of unusual acne, hirsutism, premature pubarche, or androgenic alopecia (especially when associated with obesity and/or menstrual irregularities):
    • Screen for hyperandrogenism
    • Blood levels of free testosterone, dehydroepiandrosterone, and androstenedione
    • If raised, test response of the hormones and cortisol to dexamethasone suppression

Treatment for Acne Vulgaris (Pimples)

Treatment objectives

  • Reduce severity of acne
  • Prevent complications

Drug treatment

1. Comedonal acne

Topical treatment only:

Tretinoin cream

  • Adult: 0.025% or 0.05% or 0.1% cream or gel applied nightly
  • Child: apply thinly 1-2 times daily


Benzoyl peroxide

  • Adult: 2.5% or 5% water-based or alcohol based gels, applied twice daily
  • Child
    • 12-18 years: apply 1 – 2 times daily preferably after washing with soap and water. Start with lower strength preparations Infantile acne:
    • Child 1 month to 2 years; neonate: apply 1 – 2 times daily. Start with lower strength preparations


Salicylic acid solution 2%

  • Adult and child: apply up to 3 times daily

Tretinoin may be used at night and benzoyl peroxide or topical antibiotics in the morning because they have different modes of action and are complementary.

It may take 8-12 weeks before observable improvement occurs.

2. Mild inflammatory acne

  • Treat as above

3. Moderate inflammatory acne

Topical and systemic drugs:


  • Adult and child over 12 years: 500 mg orally every 12 hours



  • Adult and child over 12 years: 100 mg orally every 12 hours



  • Adult and child over 12 years: 500mg – 1 g every 12 hours
  • Infants requiring oral therapy: 250 mg once daily or 125 mg every 12 hours



250 – 500 mg orally every 12 hours: in patients who do not tolerate any of the tetracyclines or who fail to improve.

Review patient in 6 weeks and 3 – 4 months later.

If there is marked improvement, taper the dose by 250 mg for tetracycline every 6-8 weeks while treating with topicals to arrive at the lowest systemic dose needed to maintain clearing

4. Antibiotic-resistant acne

Spironolactone may be added as an

  • Adult: 50-200 mg orally daily

5. Severe acne

Start with systemic antibiotics as above

Oral isotretinoin (13-cis retinoic acid)

  • Adult: 0.5-1 mg/kg/day for 20 weeks for a cumulative dose of at least 120 mg/kg
  • Child 12 18 years: 500 micrograms/kg once daily, increased if necessary to 1 mg/kg in 1 – 2 divided doses
  • Occasionally, acne does not respond or promptly recurs after therapy, but may clear after a second course
  • At least a 4-month rest period from the drug is recommended before a second treatment course is considered

6. Acne fulminans

Prednisolone 1.0 mg/kg daily for 7-10 days then taper off rapidly as isotretinoin is started.

Success has been reported with dapsone but only in toxic doses (100 mg three or four times daily)

Adjuvant measures

  • Use non-irritating cleansing agents to reduce facial sheen and bacterial flora
  • Emotional support
  • Comedone extraction
  • Intralesional injection for deeper papules and occasional cysts
  • Dilute suspensions of triamcinolone
    acetonide 2.5 mg/mL or 0.05 mL per lesion
  • Laser, dermabrasion for cosmetic
    improvement of scars

Notable adverse drug reactions, caution and contraindications

Creams and water-based gels are less
irritating than alcohol/acetone-based gels

Topical preparations:

  • Always initiate treatment with lower strength and increase as tolerance develops to initial irritant reaction.
  • Occasionally contact sensitivity may occur

Benzoyl peroxide

  • May bleach fabrics, hair and skin
  • Avoid contact with eyes, mouth, and
    mucous membranes
  • Antibiotic resistance may occur
  • Avoid the use of different oral and topical antibiotics at the same time
  • Vaginitis and perianal itching due to Candida may occur
  • Tetracyclines, and doxycycline are contraindicated in pregnancy and in children less than 12 years
  • May reduce the effectiveness of oral
  • Often cause GIT symptoms
  • Doxycycline may cause photodermatitis
  • Erythromycin cannot be used in
    conjunction with astemizole or
    terfenadine, as serious cardiovascular complications may occur

Salicylic acid

  • Significant absorption may occur from the skin in children.


  • Dry skin, lips and eyes
  • Decreased night vision
  • Epistaxis
  • Hypercholesterolaemia
  • Hypertriglyceridaemia
  • Pseudotumour cerebri and headaches
  • Depression
  • Musculoskeletal or bowel symptoms
  • Thinning of hair
  • Bony hyperosteoses
  • Premature epiphyseal closure in children
  • Absolutely contraindicated during pregnancy (teratogenicity)
  • Obtain informed consent before use; start oral contraceptives one month before commencing therapy and continue for another month after conclusion of therapy
  • Women of childbearing age are strongly advised to avoid pregnancy for up to 3 years following cessation of therapy –
  • Check cholesterol and triglyceride levels every 2-4 weeks while on therapy
  • Dapsone at such high doses is likely to cause methhaemoglobinemia
  • Where leprosy is still endemic (e.g. Nigeria), reserve for treatment of leprosy


  • Avoid Oil-based cosmetics, hair styling mousse, face creams and hair sprays
  • Medicines that may induce acne

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