2nd July 2023

Acne Vulgaris

Introduction

It typically presents in adolescent years and tends to be seen on the face, but it can also affect the neck, trunk, and proximal upper extremities (where sebaceous glands are abundant). It is an inflammatory disorder of the pilosebaceous unit – the hair follicle and sebaceous gland. Pathogenesis involves:

1. Plugging of the follicle secondary to epidermal proliferation
2. Excess sebum production
3. Colonisation with anaerobic Propionibacterium acnes
4. Inflammation

Contributing factors include androgen-mediated stimulation of sebaceous glands, cellular immune responses, dysbiosis of the microbiome of the pilosebaceous follicle and in some cases, it has been reported to be related to genetics, medication and possibly diet.

Investigation and Management

It is primarily a clinical diagnosis and is characterised by non-inflammatory comedones (open or closed) and inflammatory papules, pustules and/or nodules. It can be classified as mild, moderate, or severe, which informs management. There are a variety of topical treatments for mild lesions, such as with retinoids (adapalene), benzoyl peroxide and antibiotics (clindamycin).

If symptoms do not resolve with topical treatments, various systemic treatments can be considered:

•  Oral antibiotics
  • First line: tetracyclines such as doxycycline and lymecycline (contraindicated in pregnancy – can consider macrolide antibiotics however they are not recommended due to high levels of P. acnes resistance).
  • Minocycline is not recommended as there is increased risk of adverse effects
• Anti-androgenic contraceptives in females, e.g. the combined oral contraceptive pill
• Retinoid therapy – isotretinoin

Isotretinoin, a systemic retinoid, is highly effective in severe cases. It is indicated when there is scarring and when other treatment options have failed. It can only be prescribed by specialist dermatology teams. As isotretinoin is teratogenic, women of childbearing age are required to use two methods of contraception and have monthly pregnancy tests. Regular blood monitoring of liver function tests and triglycerides are also required as it can cause derangement. Side effects include dry skin (most common) and low mood.

Complications

Several complications can occur, such as:

• Post inflammatory hyperpigmentation presenting as dark spots – photoprotection is essential
• Post inflammatory erythema presenting as residual, persistent, and pink to red discolouration of the skin
• Scarring which can be managed with minor surgical procedures, laser therapy and chemical peels as well as other interventions