2nd July 2023

Acne

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

Acne Rosacea

Introduction

A chronic inflammatory skin condition that typically affects the central face and eyes. It presents with centrofacial erythema, inflammatory papules and pustules, flushing, telangiectasia and phymatous skin changes, e.g. rhinophyma.

It occurs in approximately 5% of adults worldwide and tends to affect both genders equally. It typically presents after 30 years of age and is more prevalent with age.

The pathogenesis is multifactorial and is thought to include a combination of genetic susceptibility, altered microbiome of the skin and gut, and neurocutaneous mechanisms – alcohol, UV light, exercise, temperature changes and spicy food.

Investigation and Management

Rosacea is primarily a clinical diagnosis. Differential diagnoses include acne vulgaris, skin damage, seborrhoeic dermatitis, dermatomyositis, drug reactions and eczema, to name a few.

The main treatment is through lifestyle change – patients are encouraged to record a symptom diary to identify their triggers and subsequently avoid them. Patients should moisturise frequently and use daily SPF. Exfoliants, topical steroids and alcohol-based topical products should be avoided.

Medical treatment includes topical metronidazole in mild to moderate cases. In severe cases brimonidine is used (to reduce erythema). Systemic treatment options include a 2-month course of tetracyclines (or erythromycin) and should be used if symptoms have not resolved for a year with topical therapies. In cases of telangiectasia, laser treatments can be trialled. Complications include blepharitis, keratitis and conjunctivitis. Oral antibiotics are indicated in cases of ocular involvement.