Acne Flashcards
(29 cards)
What is acne vulgaris?
Is a disease of the pilosebaceous unit or pilosebaceous follicle variably affects the face and torso characterised by a greasy skin, comedones, papules and pustules there may also be nodules, cysts and scarring
What is the pathogenesis of acne vulgaris?
An increase in sebum excretion by the sebaceous glands
Hypercornification of the follicular lining leading to obstruction of the pilosebaceous ducts
Overgrowth of the bacterium propionibacterium acnes within the pilosebaceous ducts and subsequent inflammation
How do androgens effect acne?
Promote sebum production and excretion
Surges occur in adrenarche and puberty
Decreased level of sex hormone-binding globulin may also play a role
hypersensitivity of the sebaceous gland to normal circulating androgens occurs
Hyperandrogenic states, PCO and other tumours
How are the microcomedo formed?
Sebum excretion rate increases (androgen or irritant effects of sebaceous lipids)
Keratinocyte cells lining these ducts show abnormal differentiation: hyperkeratosis, and abnormal shedding
Retention of the cell lining and resultant occlusion of the ducts- forms microcomedo (blocked pore, primary lesion of acne)
How is inflammation caused in acne?
P. acnes proliferate in the sebum rich environment produces chemotactic and pro-inflammatory mediators
Substances then diffuse through the follicular duct into surrounding dermis
Influx of neutrophils and complement activation
Rupture of the follicle with leakage of the follicular contents into the dermis - foreign body type reaction and further inflammation
What are open comedones (blackheads)?
Distended pilosebaceous unit with a dilated orifice which is impacted with keratin and lipid
The impacted material appears dark because of oxidation of melanin, the lesions themselves are flat or slightly raised Blackheads can go on to become inflamed
What are closed comedones (whiteheads)?
No clinically visible opening to the skin surface
they more likely to become inflamed than open comedones as the follicles can burst more easily
When they burst they release irritant free fatty acids and cause papules and pustules- superficial inflammatory lesions, may last between 1 and 2 weeks
What are the deep inflammatory lesions of acne?
Nodules- often painful, last weeks to months, occur when there is an excessive inflammatory response in the surrounding dermis
True cysts- abscess formation (acne conglobate, rare type)- highly inflammatory disease starts in adult life
What occurs with the resolution of superficial inflammatory lesions?
Erythematous macules, hyperpigmentation-seen mainly in dark-skinned patients or hypopigmented macules
Often transient and don’t cause scarring
What scars are associated with a loss of collagen?
Ice-pick scars
Macular atrophic scars
Deep atrophic scars
Depressed fibrotic scars
What scars are associated with increased collagen?
Hypertrophic scars
Keloid scars typically occur on the upper back, chest and shoulders
What can aggravate acne?
Oily cosmetics and hair greases as they are comedogenic
Facial saunas, heat and massage may precipitate the development of inflamed lesions as can vigorous or excessive washing
Squeezing lesions
High progesterone containing oral contraceptive pills, and potent topical or oral steroids can all worsen existing acne or precipitate lesions of acne
When does acne vulgaris occur?
85% of those aged between 12 and 24 years old
It usually starts at puberty but can occur just prior to the onset of puberty, and will therefore occur sooner in females than males
Affects boy more in adolescence
What are the other subtypes of acne?
Cystic acne or acne conglobate
Acne fulminans
Acne excoriee
Neonatal acne
Infantile acne- between 3-12 months, mainly males and facial, treated with erythromycin
Endocrine acne- PCOS, Cushing’s disease, etc
Occupational acne: cutting oils, crude tars, atypical sites where soaked clothing in contact with skin
Tropical acne: young Caucasians in hot humid climate, gross acne lesions on the trunk
Cosmetic acne
Medication acne (steroid) monomorphic lesions mainly on the trunk, in patients on systemic steroid
What are retinoids?
vitamin A derivatives, in topical form these agents are comedolytic, which means they remove the surface keratin - essentially unblocking the pores and allowing drainage of microcomedonal contents
They secondarily prevent the formation of new acne lesions
First line for comedonal acne and need to be prescribed
Teratogenic even as topical agents, not to be used in pregnancy or while breast feeding
Photosensitivity can occur, erythema and irritation
When is benzyl peroxide?
Antibacterial agent
Azelaic acid cream rarely used
Mild to moderately severe papulopustular acne
Preparations can bleach clothes
When is the commencement of systemic antibiotics indicated?
Lymecycline and doxycycline
Erythromycin (can be used in pregnancy- GI effects)
Trimethroprim 3rd line
6 weeks for efficacy then try other one
If topical treatments haven’t worked
Presence of acne scarring, marked post- inflammatory skin changes, or the involvement of the chest and back
Should always be commenced with a retinoid and BPO
What are the side effects of cyclines?
Contra-indicated in pregnancy and breast feeding and in children under 12
Effect bone growth, foetus and cause discolouration of growing teeth
What occurs with antibiotic resistance?
Seen more commonly when using erythromycin, where staphylococcal resistance is also seen, no routine testing is available and therefore clinical judgement is important
Resistance may be limited by combining therapy with topical treatments- 6 months or less
What are the hormonal treatments for acne?
Dianette, an oral contraceptive pill that contains an oestrogen ethinyloestradiol and the anti- androgen cyproterone acetate
Used for clinical signs of hyperandrogenism, those with acne flares at their menstrual periods or those with seborrhoea and persistant inflammatory lesions on the lower face
As effective as oral antibiotic
Contraindicated in breast feeding, pregnancy, history of DVT and embolic disorders
When is isotretinoin used?
Severe acne
Active acne with scarring
Resistant disease
Where rapid relapses on cessation of oral therapy
Acne leading to psychological/psychiatric disease
What are the side effects of isotretinoin?
Highly teratogenic Dry skin Chellitis Dermatitis Dru mucosa Epistaxis Hair loss Severe depression? Fasting lipids, LFTs, FBC are performed before and 1 month into treatment Monthly pregnancy tests 4-6 months treatment 22-30% relapsing
What are the treatments for acne scarring?
Microdermabrasion or dermabrasion for superficial scarring
Laser resurfacing may be used to improve the appearance of atrophic scars, but risks leaving permanent pigmentory changes including hypopigmentation that may only be visible some years later on fair or pigmented skin
Large ice-pick scars may be removed with punch biopsy Keloid scars may be treated with intralesional steroids
What is acne fulminans?
Occurs after unsuccessful treatment of acne conglobata
Rare
Pain and inflammation in joints, lymphadenopthy at base of neck
Loss of weight and atrophy of muscles
Hepatosplenomegaly
Debridement and steroid therapy is used to treat
Males aged 13-22
