Acne vulgaris

Notes
  • This is a disease that is characterized by comedones, papules, pustules, nodules, and/or cysts due to obstruction and inflammation of hair follicles and sebaceous gland (pilosebaceous glands).
  • Acne affects about 9.4% of the global population (mainly adolescents). In Kenya, some studies have found a prevalence of acne in Western Kenya to be 11.2%.
  • In acne there is increased sebum production, follicular plugging with sebum and keratinocytes, colonization of follicles by Propionibacterium acnes (a normal skin colonizers) and involvement of various inflammatory mediators.
  • Acnes are classified into two broad categories: Noninflammatory acnes (or comedonal acnes) that are characterized by comedones (which are sebaceous plugs impacted within follicles) and inflammatory acnes that are characterized by papules, pustules, nodules, and cysts.
  • Comedonal acne can be open or closed depending on whether the follicle is dilated or closed at the skin surface.
  • In inflammatory acne papules and pustules Propionibacterium acnes colonizes the closed comedones and degrades sebum into fatty acids that irritate the follicular epithelium. This leads to inflammatory response that disrupts the epithelium even more. The inflamed follicle ruptures into the dermis where the comedone contents produce further local inflammatory reaction generating papules. If the inflammation is intense, purulent pustules are produced. Nodules are deeper lesions that may involve more than one follicle while cysts are large fluctuant nodules.
  • Factor favouring manifestations of acne: puberty, hormonal changes (e.g. pregnancy and the menstrual cycle), drugs and high humidity.
Symptoms
  • Closed plugged pores (whiteheads)
  • Open plugged pores (blackheads)
  • Papules (small red, tender bumps)
  • Pustules (pimples)
  • Nodules (Large, solid, painful lumps beneath the surface of the skin)
  • Cystic lesions (painful, pus-filled lumps beneath the surface of the skin)
  • Crusting of skin bumps
Diagnosis
  • Clinical diagnosis
  • Hormonal evaluation tests in suspected cases: total and/or free testosterone, dehydroepiandrosterone sulfate, luteinizing hormone, and follicle-stimulating hormone
  • Culture of skin lesions in cases that are refractory to treatment (to rule out gram-negative folliculitis)
Differential
  • Dermatologic Manifestations of Tuberous Sclerosis
  • Folliculitis
  • Milia
  • Perioral Dermatitis
  • Pyoderma faciale
  • Rosacea
  • Syringoma
Prevention
  • Washing the face (twice per day is good)
  • Avoiding touching or picking at the pimple.
  • Avoid excessive make-up
Management
  • Comedonal acne

* Adapalene cream at bedtime  or  *Tretinoin cream at bedtime or  *Benzoyl peroxide 5% applied  at bedtime. Progress up to 10% when necessary or

*Fixed-dose combinations adapalene–benzoyl peroxide topically at bedtime or

*Clindamycin–benzoyl peroxide at bedtime or

*Clindamycin 1.2% and tretinoin 0.025% (as a gel) at bedtime

*For women, oral contraceptives may improve treatment outcome when added to the above treatment.

  • Localized mild-to-moderate papulopustular acne

*The medicines and dosage under “Comedonal acne” above.

  • More extensive moderate papulopustular acne

*The medicines and dosage under “Comedonal acne” above and addition of the following systemic antibiotics for more than 12 wks (this may be given concomitantly with topical antibiotics): Either,

** Caps Tetracycline 250 or 500mg BD for 4 wks until satisfactory results are achieved. Then maintenance dose of 250 or 500mg OD is given OR

** Caps Minocycline 50 or 100mg BD for 4 wks until satisfactory results are achieved (NB: it causes less GIT and photosensitization   side effects in comparison Tetracycline. However, on long term use it causes more side effects) OR

** Caps Doxycycline 100mg BD (sub-optimal doses of 20, 50 and 75mg BD have also been shown to be effective). Photosensitization is a major challenge with Doxycycline) OR

**Tabs Azithromycin thrice weekly  for 8 wks (better tolerated and compliance than Erythromycin) OR

** Tabs Erythromycin 250 -500mg BD (useful in pregnancy where tetracyclines are contraindicated).

  • Severe acne

* Oral isotretinoin

0.5 -1.0mg /kg daily [OD or in 2 divided doses] with meals. Dose adjusted after 4 weeks depending on response or side effects OR

*Systemic antibiotics highlighted under “More extensive moderate papulopustular acne” in combination with benzoyl peroxide, with /without topical retinoids.

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