Acne, scabies & lice (skin 8) Flashcards
what is the difference between psoriasis and eczema?
psoriasis:
- chronic, lifelong disease
- common in adults
-hederdiatry
-characterised by thick, silver scales
eczema
- condition that can come and go
- common in children
- thought to be environmental
-skin being red and imflammed
Atopic dermatitis (eczema)
aetiology
pathophysiology
clinical features
treatment
aetiology: Idiopathic, genetic; family history of atopy; Environmental triggers
Pathophysiology: Abnormal IgE activity mediated by B lymphocytes
clinical features:Dry scaly thickened skin often on flexural surfaces; common in children
Treatment: Corticosteroid creams; emollients; wet dressing
Psoriasis
aetiology
pathophysiology
clinical features
treatment
Idiopathic, genetic; triggered by trauma, stress, infection
Abnormal T cell activity; excess / hyperproliferation of skin cells
Skin plaques “silvery” scales; rough red and raised skin; common on extensor surfaces
Emollients; Vitamin D analogues and corticosteroid; UV light; coal tar; monoclonal antibodies
Contact dermatitis; allergic / irritant
aetiology
pathophysiology
clinical features
treatment
Contact leading to irritation; irritant (most people react to) or allergic (some people respond to)
Abnormal T cell activity mediated by T lymphocytes
Red / burning itchy vesicles on skin surface. Irritant located at site of exposure (but may spread); allergic not localised to exposure site
Avoid irritant; corticosteroid; calamine; antihistamine for itch
what are the hazards for emollient?
Emollients are not flammable in themselves, or when on the skin.
But advise patients to avoid naked flames & halogen heaters near clothing / bedding / dressings
what are emollients?
why does it not have an API ?
Lots of options available:
Creams, ointments, gels, lotions, sprays, washes, (and bath / shower additives)
Emollients containing API’s not generally recommended
Increased risk of skin reactions.
But may be useful for some people.
- emollients are prescribed according to the dryness of the skin and individual preferences/ tolerance.
-creams and lotions = red, inflamed skin ( evaporation of water based products can cool the skin) - do NOT advice aqueous cream
- ointment = dry skin which is NOT inflamed.
- recommend an emollient with a pump to minimize the risk of bacterial contamination and ease the use.
-For emollients that come in pots, advise that using a clean spoon or spatula (rather than fingers) to remove the emollient helps to minimize contamination.
Emollients can replace soap in people with dry skin requiring treatment.
Ointments dissolved in hot water are suitable soap substitutes.
Bath additives and shower products are an option for people with extensive areas of dry skin
Evidence to support their use is limited and no consensus on their benefit
If bath emollients are used, it is essential that they do not replace standard emollients.
The effectiveness and acceptability of a particular emollient may vary with time.
If the person feels that a particular product has become unsuitable for them (or if they have developed sensitivity to it), recommend an alternative emollient.
It may be necessary to try a range of emollients before the person settles on the best combination.
Dispense generous amounts (eg 500 g) to be used regularly (often four times daily). - To encourage appropriate usage
what are the adverse effects from emoillients?
Skin reactions are the most common adverse effects of emollients.
Due to skin sensitising additives;
perfumes, preservatives, and biological components, such as lanolin (although newer hypoallergenic formulations of lanolin are less problematic).
If a skin reaction occurs, stop the emollient and use a different one.
If the person has had previous skin reactions to emollients, consider testing a small quantity on the skin before widespread application.
If sensitivity to emollients is a known problem, prescribe a cream with few additives, or an ointment (ointments do not require preservatives and generally have less excipients), to reduce the chance of a further reaction.
The occlusive effect of ointments can cause folliculitis. If this occurs, stop the ointment (consider switching to a cream), and prescribe an antibiotic, if necessary.
what is the advice for emoillents?
Advise to use liberally and frequently, even when their skin appears improved or is clear.
- It is recommended that 250–500 g of emollient be applied every week.
- Frequency of application will vary, but for very dry skin, application of an emollient every 2–3 hours is normal.
To facilitate frequent application, the person should consider keeping separate packs of emollients at work or school.
Important to use emollients during or after washing.
Emollients should be applied by smoothing them into the skin along the line of hair growth, rather than rubbing them in.
Can use better tolerated products (such as creams and lotions) during the day, and ointments (which are usually poorly tolerated) at night.
Emollients should not be shared with other people as they can become contaminated with bacteria.
Avoid the use of soaps, detergents, and bubble bath when washing; use a suitable soap substitute instead
(People who need to use large quantities (more than 100 g) of any paraffin-based product should regularly change clothing, bedding, or dressings which become impregnated with the product and keep away from naked flames, as there is a risk of fire)
what is acne vulgaris characterised with?
Skin condition characterised by formation of:
comedones (blackheads and whiteheads),
papules (pinheads), skin elevation, no fluid 5-10 mm diameter
nodules (like a papule but bigger than 5-10 mm)
cysts (cavity usually containing fluid)
Can be inflammatory or non-inflammatory
Commonly appears on face and shoulders, but may occur on trunk, arms and legs
what causes acne vulgaris?
Occurs when hair follicles and associated sebaceous gland become obstructed with sebum/dead keratinocytes. Can become infected with normal skin anaerobe, Cutibacterium acnes (name recently changed from Propionibacterium acnes), leading to inflammation
Lipases from C. acnes metabolise triglycerides into free fatty acids, which irritate the follicular wall. Pustules occur when active C. acnes infection causes inflammation within the follicle.
Nodules/cysts appear when inflamed follicles rupture
who does acne vulgaris happen to?
triggers
Commonly occurs in adolescence but can arise at any age, including as an infant
Tends to run in families
Most common trigger is puberty, when get surges in androgen that stimulates sebum production and hyperproliferation of keratinocytes.
Other triggers include:
- hormonal changes in pregnancy or menstrual cycle
- occlusive cosmetics, cleansing agents and clothing
- excessive humidity and sweating
- stress
-certain drugs (e.g. oral contraceptives, corticosteroids,
testosterone, oestrogen, and phenytoin)
what are the classification of acne vulgaris?
Classification of Acne Severity
Mild
< 20 comedones, or < 15 inflammatory lesions, or < 30 total lesions
Moderate
20 to 100 comedones, or 15 to 50 inflammatory lesions, or 30 to 125 total lesions
Severe
> 5 cysts, or total comedone count > 100, or total inflammatory count > 50, or > 125 total lesions
what is the treatment for acne?
Main aim is to reduce sebum production, comedone formation, inflammation and infection
Selection of treatment depends on severity
Affected areas should be cleansed daily (extra washing, scrubbing, use of antibacterial soaps confer no added benefit)
Changes in diet unnecessary
Mild to moderate usually treated topically
Moderate to severe usually systemic antibiotics (or when topicals failed)
Severe refer to dermatologist; may need aggressive therapy e.g. Isotretinoin
what are treatment options available for mild acne?
Comedones and inflamed lesions respond well to benzoyl peroxide.
- Usually start low dose and increase if necessary
- 2.5 to 5% then up to 10% - Possible local skin irritation, usually subsides with time
- If no response in 2 months, then consider topical anti-bacterial
As a peroxide (as in hair bleach), is metabolised to benzoic acid and oxygen free radicals
- Benzoic acid decreases pH
- Oxygen free radicals are bactericidal, and can also break down keratin so are comedolytic
- Benzoyl peroxide also available with clindamycin (antimicrobial)
Azelaic acid an alternative
- Anti-microbial and anti-comedonal
- Less likely to cause local irritation than benzoyl peroxide - Patients may prefer, especially for face
Topical retinoids (e.g. tretinoin / adapalene) effective for comedones and inflamed lesions
- Can be irritant, initially giving redness/peeling
- Avoid in pregnancy, avoid sun exposure
Others:
Topical antibacterials (clindamycin / erythromycin) not widely used, tend to be ineffective used alone
Salicylic acid preparations are available
- Keratolytic
- Not as suitable as other preparations
Sulphur / abrasive formulations available but not considered beneficial
Topical corticosteroids should NOT be used (increases sebum secretions)
