Case 8- Acne and skin cancer Flashcards
Who does acne effect
Mainly young people between 12-24. Acne is more common in puberty as there is an increase in androgens
What does acne consist of
It is made from a mixture of non-inflamed and inflamed lesions. Non-inflamed lesions are comedones and can be open (blackheads) or closed (whiteheads). Inflamed lesions are called papules and postules.
Process of acne development
- Androgens increase sebum production in enlarged sebaceous glands.
- Follicles become impacted and distended by altered keratinocytes and sebum (comedones- blackheads, whiteheads)
- Proliferation of bacteria within the sebum (Propionibacterium acnes)
- Inflammation of the pilosebaceous unit.
- Inflammatory lesion (pustules, papules)
Biopsychosocial effects of acne
Acne can be very severe and cover extensive areas of the body including the face, chest and back. The lesions themselves can cause distress as well as long term skin changes resulting from then such as scarring and post-inflammatory hyperpigmentation. It can have psychological impacts such as: depression, anxiety, suicide, low self-esteem and reduced attachment to friends.
Basic advice given to patients on how to manage their acne
- Avoid over cleaning the skin as this can cause dryness and irritation, acne is not caused by poor hygiene
- Avoiding wearing make-up if possible, and if make-up is to be worn to try to use non-comedogenic preparations
- Avoiding picking and/or squeezing spots - can lead to scarring
- Maintaining a healthy diet
Principle of step wise approach to acne treatment
At each stage the treatment is given 8-12 weeks to work before moving on. Treatment may irritate the skin initially. If treatment is working continue for at least 12 weeks
Acne- single topical treatment
First treatment given. Can be a topical retinoid i.e. adapalene, Benzoyl peroxide. A topical antibiotic can also be given i.e. clindamycin, it will need to be given with benzoyl peroxide to prevent resistance.
Acne- Topical retinoid’s mechanism of action
Reduces comedones, is anti-inflammatory
Acne- oral antibiotics
Antibiotics such as lyme cycline or doxycycline, given for a maximum of 3 months. Needs to be given with benzoyl peroxide to prevent resistance. The combined oral contraceptive can be given to women as an alternative to antibiotics. You continue from 3 months after acne is controlled but then you stop it due to risks i.e. blood clot.
Benzoyl peroxide mechanism of action
1) Reduces comedones
2) Reduces sebum production
3) Inhibits growth of P.acnes bacteria
Mechanism of action of topical/ oral antibiotics
1) Anti-inflammatory
2) Anti-infective
Mechanism of action of combined oral contraceptive pill
Anti-androgen
Mechanism of action- Isotretinoin
Reduces sebum secretion
The third stage in acne treatment
• Refer to dermatology if they haven’t responded to two courses of antibiotics, it is severe acne associated with visible scarring, it is causing significant psychological distress and there is diagnostic uncertainty (unsure if its acne).
Specialist acne treatment
Once referred to dermatology, they will consider treatment with oral isotretinoin (a retinoid)
Contraindications of topical and oral retinoids
Topical and oral retinoids (adapalene, isotretinoin) are teratogenic so are contraindicated in pregnancy.
Contraindications of Tetracycline antibiotics
Tetracycline antibiotics (lymecycline, doxycycline) are also teratogenic and contraindicated in pregnancy.
Side effects of isotretanoin
As well as being teratogenic, isotretanoin has the potential for severe side effects and therefore can only be prescribed in hospitals under consultant supervision. Other side effects include dry skin, skin thinning, depression and mood swings. Don’t use when pregnant
The psychological impact of skin cancer
Surgical removal of skin cancer can be disfiguring especially on the face
Most common skin cancer order
1) Basal cell carcinoma- 75%
2) Squamous cell carcinoma
Why do most cancers occur in the epidermis?
They are exposed to UV
What gives rise to squamous cell carcinoma?
Keratinocytes give rise to Actinic Keratosis which is a precursor to squamous cell carcinoma.
What’s the most deadly skin cancer
Melanoma, derived from melanocyes
Role of melanin
Normally melanin gets packages in Melanosomes which get deposited into the keratinocytes and basal cells. The melanin covers the nucleus of the cell protecting it from UV radiation, which could cause mutations and cancer.
NMSC (non-melanoma skin cancer)
Refers to basal cell carcinoma, Actinic Keratosis and squamous cell carcinoma. Accounts for 90% of diagnosed skin cancers
Skin cancer epidemiology
Skin cancer is the most commonly diagnosed cancer in the UK and worldwide. There are more cases in hotter countries where the population have lower amounts of melanin i.e. Australia and USA.
Skin cancer and UV
95% of skin cancers are due to exposure to UV light and sunlight. The UV directly damages the DNA causing a thymidine dimer. In a thymidine dimer the T nucleotides join to each other forming kinks in the structure. The thymidine dimers cause DNA/DNA crosslinking. The UV can also indirectly damage DNA by damaging cells and creating free radicals which mediate oxidative DNA damage. This all leads to the activation of oncogenes and the inactivation of tumour suppressor genes. Leading to unregulated cell growth
How UVA damages DNA
Causes ageing and wrinkling, it is the longest wavelength and damages all layers of the skin (surface, epidermis and dermis)
How UVB damages DNA
Causes burning, it is medium wavelength and penetrates the skin surface and epidermis.