Acne vulgaris
D E FI N I T ION
Inflammation of the pilosebaceous unit of the skin.
AE T IOLOGY
Increased production and impaired normal flow of sebum (caused by
follicular hyperkeratinization and obstruction of the pilosebaceous duct) leading to inflammation
and formation of closed or open comedones. The bacteria Propionibacterium acnes,
Staphylococcus epidermidis and Pityrosporum yeast may be involved in pathogenesis.
Associated with polycystic ovarian syndrome, cortisol excess (Cushing’s syndrome), prolactinoma
and puberty.
E P IDEMIOLOGY
Ubiquitous. Begins in puberty and tends to recede with age.
H ISTORY
Usually self-diagnosed, acute onset, greasy skin, may be painful.
EXAMINA T I ON
Open comedones (whiteheads: flesh-coloured papules), closed comedones
(blackheads: the black colour is caused by oxidation of melanin pigment), papules,
pustules, nodules, cysts and seborrhoea primarily affecting the face, neck, upper torso and
back. Three grades: mild, moderate and severe.
INVE S T I G A T IONS
Normally none required, especially if experiencing puberty.
Blood: LH levels (increased LH: FSH ratio may be seen in PCOS), prolactin, sex-hormonebinding
globulin, testosterone, 17-OH-progesterone (9 a.m., follicular phase; if congential
adrenal hyperplasia is suspected).
Urine: 24-h urinary cortisol (if Cushing’s syndrome suspected).
Imaging: Pelvic ultrasound (if PCOS suspected).
MANAGEMENT
: Start treatment early to prevent scarring.
For mild/moderate acne: Over-the-counter preparations containing benzoyl peroxide,
azelaic acid.
For moderate/severe acne: Consider topical antibiotics (clindamycin, erythromycin),
topical vitamin A derivatives (tretinoin).
For severe inflammatory acne or if failure of topical treatment:
Consider systemic antibiotics (oxytetracycline, minocycline, erythromycin).
For severe acne: Also consider oral vitamin A derivative (isotretinoin) – available only by
specialist prescription.
Side effects: Teratogenic, hyperlipidaemia.
For females: Oral contraceptive pill or cyproterone acetate reduces severity.
Advice: Counsel patients that an improvement may not be seen for a couple of months, use
of non-greasy cosmetics, wash face daily.
COM P L IC A T I ONS
Facial scarring (atrophic, ‘ice pick’, hypertrophic, keloidal), hyperpigmentation,
secondary infection, psychological morbidity.
PROGNOSIS
Generally improves spontaneously over months or years
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