PCC2 Special Senses - The Skin

Eczema An itchy red eruption consisting of patches or papules (solid elevation of the skin). What is the most common form of eczema in children ? Atopic eczema - most common form of eczema in children - affects between 10-20% of all school age children - affects both sexes equally Epidemiology of Atopic eczema ? Acute eczema - An inflammatory process, which leads to oedema (fluid) in the epidermis - Fluid collects into tiny blisters which can then join together - Fluid is lost through the skin causing the skin cells to separate - This allows for the ingress of chemicals, allergens and pathogens (bacteria) Describe what happens during an acute to cause inflammation and a defective skin barrier eczema flare up ? Chronic eczema Thickened epidermis = due to prolonged rubbing and scratching Describe the appearance of the skin in chronic eczema ? - Thick - Scaly - Leathery 1/8 Forms of eczema - Atopic eczema - Contact dermatitis - Seborrheic dermatitis - Discoid eczema - Stasis eczema - Asteatotic eczema Factors that can exacerbate eczema ? - Extremes of temperature - Irritants e.g., soap and bubble baths - Stress - Bacterial/viral infection - Contact/food/inhaled/airborne allergens What are the most commonly affected areas in infant and childhood eczema ? Face and back of the knees What is involved in the treatment of eczema ? - Emollients = first line treatment of eczema - Topical corticosteroids Examples of emollients ? - Aqueous cream - E45 cream - Diprobase Aqueous cream - Side effects - Stinging - Burning - Itching - Redness E45 cream - Side effects Occasionally, allergic reaction or worsening of acne may occur. Diprobase - Side effects Skin reactions including: - pruritus - rash - erythema - skin exfoliation - burning sensation - hypersensitivity - pain - dry skin - bullous dermatitis 2/8 - Corticosteroid must be absorbed - Importance of concentration, occlusion, type of vehicle, added penetrants (e.g., What is necessary for a topical corticosurea) teroid to be effective ? and - Anatomical site on the amount of absorption and on clinical activity has been demonstrated. Their non-specific anti-inflammatory efWhat is the main therapeutic activity of fect, this is a primary result of their action topical corticosteroids ? on the chemical mediators of inflammation. Advantages of topical use of corticosteroids ? - Deliver high concentrations to a target site - Reduce the side effects resulting from systemic administration - Significant systemic absorption occurs at higher doses - Low-potency corticosteroids should be Why should low-potency corticosteroids selected for continuous use to avoid side be used in the treatment of skin disor- effects ders ? Examples of corticosteroids drugs? - Hydrocortisone - Betamethasone - Clobetasol - Clobetasone Hydrocortisone - Topical formulation E.g., Cream or Ointment Indicated for - Mild inflammatory disorders (eczema) - Less potent E.g., Cream, Ointment, Scalp preparation, medicated plaster, lotion and foam Indicated for - Severe inflammatory dis3/8 Betamethasone - Topical formulation orders (eczema unresponsive to less potent corticosteroids and psoriasis) - More potent = not to be used for long-term treatment Clobetasol - Topical formulation E.g., Cream, Ointment, Scalp preparation, Foam and Shampoo Indicated for - Short-term treatment only of severe resistant inflammatory skin disorders - Very potent = used only for short-term treatment of resistant eczema Clobetasone - Topical formulation E.g., Cream and Ointment Indicated for - Eczema and dermatitis of all types What class of corticosteroids are Hydrocortisone and Betamethasone ? Glucocorticoid receptor agonists - Via esterification of one, or more, hydroxyl groups = due to this many corticosteroids are given as phosphate esters. How can improved dermal absorption be achieved with the application of topical Esterification of the C-21 hydroxyl group: application ? - determines the extent of hydrophobicity within the molecule - controls the deposition of the compound The C-16 substituent counteracts minWhat happens when a C-16 substituent eralocorticoid activity = explains the in(e.g., a methyl group) is introduced to a creased potency observed over that of corticosteroid molecule ? hydrocortisone which lacks a C-16 substituent. Psoriasis A chronic relapsing inflammatory disorder characterised by a variety of morphological lesions present in a number of forms. 4/8 What is the most common form of Psori- Plaque psoriasis - accounts for 80-90% asis ? of cases - Common skin disorders = estimated worldwide prevalence between 1-3% - In UK = affected 1-2% of the population (could be an underestimate, many patients with mild psoriasis do not present to their doctor) Explain the epidemiology of Psoriasis ? - Can present at any time in life, appears to be more prevalent in 2nd and 5th decade - Rare in infants and uncommon in children - Sexes are equally affected - More common in Caucasians - An immune mediated disorder with a genetic influence (exact aetiology is still unclear) - PSORS1 region on chromosome 6 is a contributor to psoriasis susceptibility Explain the pathophysiology of psoriasis - Environmental factors may be need? ed for clinical expression of the genes (shown in studies on twins) Lesions develop at sites of: - Skin trauma e.g., sunburn and cuts (Koebner phenomenon) - Following streptococcal throat infection - During periods of stress Koebner phenomenon When psoriasis lesions form in different areas than usual. 5/8 Signs and Symptoms of Plaque Psoriasis ? - Salmon-pink lesions with silvery white scales and well-defined boundaries (not apparent of darker skin) - Lesions can be single or multiple, they can vary in size and cover an extensive area. Auspitz' sign If the scales on the surface of the plaque are gently removed and the lesion then rubbed, it reveals pinpoint bleeding from the superficial dilated capillaries. Forms of psoriasis ? - Pustular - Flexural - Seborrhoeic - Erythodermic - Plaque Treatment of Plaque Psoriasis - Topical treatments = first line treatment for psoriasis - Systemic treatments = available, but generally reserved for extensive psoriasis or patients non-responsive to topical therapy Drugs involved in the treatment of Psoriasis ? - Emollients - Keratolytics - Coal tar (or dithranol) - Vitamin A & D analogues - Steroids Name some examples of vitamin D analogues ? - Calcipotriol - Calcitriol - Tacalcitol Used to help soften scaling and soothe Treatment of Plaque psoriasis - Emolthe skin, reducing irritation, cracking and lients dryness. E.g., Salicylic acid, Lactic acid - Incorporated into emollients to aid clearing scales 6/8 Treatment of Plaque psoriasis - Keratolytic's - Should be used first when significant scaling is present before other treatment options Treatment of Plaque psoriasis - Coal tar - Coal tar has a beneficial effect, but also drawbacks It is difficult to assess the effectiveness of coal tar preparations as their is variWhat is a drawback associated with the ability in their composition. This makes use of coal tar for psoriasis treatment ? meaningful comparison between clinical studies difficult. - A systematic review demonstrated a statistically significant improvement over placebo Treatment of Plaque psoriasis - Dithranol - Current practice = start on lowest possible concentration, gradually increasing the concentration until improvement is noticed. When can a improvement in psoriasis be Usually seen in 2 weeks - continues for seen with the use of vitamin D analogues at least 8 weeks. ? Usually well tolerated - any side effects Side effects of topic treatments - Emolexperienced are generally related to senlients sitisation reaction caused by excipients. Side effects of topic treatments - Coal tar - Unpleasant smell - Skin irritation - Folliculitis - Stain clothes Side effects of topic treatments - Dithranol - Skin irritant - Stains skin and hair Side effects of topic treatments - Vitamin D analogues - Skin irritation - Photosensitivity High usage (>100g): - Depression of serum parathyroid - Skin irritation - Burning 7/8 - Erythema Side effects of topic treatments - Vitamin Must not be used for pregnant or breastA analogues feeding women Side effects of topic treatments Steroids - Skin atrophy - Telangiectasia 8/8