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DERMATOLOGIC THERAPY. Dr.MOHAMED NASR Lecturer Of Dermatology & Venereology. I. Topical therapy. In medicine, a '''topical''' medication is applied to body surface such as the skin or mucous membranes. CLASSES OF TOPICAL PREPARATIONS. Solutions
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DERMATOLOGIC THERAPY Dr.MOHAMEDNASRLecturer Of Dermatology & Venereology
I. Topical therapy • In medicine, a '''topical''' medication is applied to body surface such as the skin or mucous membranes.
CLASSES OF TOPICAL PREPARATIONS Solutions These are a powder dissolved in a base of water or alcohol.
Lotions • Lotions are similar to solutions but thicker and more emollient. They are usually oil mixed with water.
Shake lotions • These are suspensions of fine powders in oil mixed with a water-based solution. The mixture separates with time so it needs to be shaken well into suspension before usage.
Emulsions • These are oil in water emulsions, they are more stable than shake lotions and less drying than lotions
Cream (hydrophilic ointment) • A Cream is a semisolid compound of oil (or petrolatum) and water in approximately equal proportions stabilized with a detergent such as sodium lauryl sulphate. • Cream is thicker than lotion. • It has a good penetration power of the stratum corneum.
Ointment • An '''ointment''' is a homogeneous, viscous, semi-solid preparation of the active ingredient in a greasy, thick oil or white soft paraffin (petrolatum) with a concentration of oil 80% and water 20%.
Gel • Gels are thickened aqueous lotions. • They are often a semisolid emulsion of high molecular weight polymers in an alcohol base. • Gels and lotions are especially suitable for treatment of the scalp and other hairy areas as well as body folds.
Collodions • They are liquid preparations consisting of cellulose nitrate in an organic solvent. • They evaporate rapidly to leave a flexible film holding the medicaments in contact with skin.
Transdermal patch • A method of delivering a drug by diffusion to the skin.
Powder • Powder is either the pure drug by itself or the drug is mixed in a carrier such as corn starch.
Solid • Some medications are placed in a solid form such as deodorants, antiperspirants and astringents. • Some solids melt when they reach body temperature e.g. rectal suppositories.
Tape • Topical applications may be used under occlusion by a tape. This greatly increases the potency and absorption of the topical agents.
Paste • Paste is a semisolid preparation, thicker and drier than an ointment. • Protective fatty paste is a suspension of a powder such as zinc oxide or starch in a greasy ointment base. It is greasy and water insoluble. It acts as occlusive, protective and hydrating agent. • Drying paste (cooling paste) is a mixture of powder with liquid so it is non greasy and water miscible and easy to apply and remove. It acts as a drying and soothing agent.
1-Topical steroids: Indications: • Dermatitis • Lichen planus • Alopecia areata • DLE • Psoriasis
Side effects: • Epidermal atrophy. • Impaired wound healing. • Persistent vasodilatation and telangiectasia. • Hypopigmentation (melanocyte inhibition). • Striae due to collagen synthesis inhibition. • Acneiform eruption. • Suppression of inflammatory signs of infectious cases as impetigo contagiosa followed by marked exacerbation of the condition after stoppage of steroids. • Scabies and fungus infection clinical pictures may be modified by the use of steroids leading to scabies incognito and tinea incognito.
Indications for intralesional steroid injection • Keloid • Hypertrophic lichen planus • Alopecia areata • Nodulocystic acne • DLE • Post scabietic nodules
2-Topical retinoids: • Tretinoin0.1% and isotretinoin0.05% cream and gel are used for acne, melasma and solar lentigenes. • They may cause dermatitits and irritation. • Adapalene0.1% gel is less irritant and better tolerated.
Antihistamines Indications: itchy skin diseases as: • Generalized pruritus • Atopic dermatitis and other types of eczema • Urticaria and angioedema • Scabies • Lichen planus
Types of antihistamines : 1- H1 receptor antagonists • First generation(sedation & atropine like effect). • Second generation (do not cross the blood brain barrier, so do not cause drowsiness, they also have longer action).
2-H2 receptor antagonists • They are antagonists for H2 histamine receptors, found principally in the parietal cells of the stomach. • They can be combined with H1 antihistamines in chronic urticaria
Systemic steroids Indications: • Acute anaphylactic reactions. • Autoimmune diseases: pemphigus, pemphigoid, Behcet's. • Connective tissue diseases: SLE, Dermatomyositis, systemic sclerosis. • Lichen planus: oral ulcerative lichen planus, destructive nail involvement and generalized lichen planus. • Disseminated or extensive cases of eczema.
Antimalarials • They are indicated in: lupus erythematosus especially DLE and solar urticaria.
Dapsone • It is indicated in leprosy and acne conglobata.
Ivermectin • It is effective against Sarcoptsscabiei. • Dose in scabies is 200 μg / kg repeated in 7 to 14 days. • Side effects: (rare and usually minor) Transient tachycardia Flushing Nausea Diarrhea Skin rash
Oral retinoids • Oral retinoids are synthetic derivatives of Vitamin A (retinol). • They have a role in normalization of skin differentiation and keratinization.
Etretinate: • It is the parent of retinoids. Acitretin: • It results from hydrolysis of etretinate and is now superior to it. • It is used in extensive forms of psoriasis especially erythrodermic and pustular forms. • It is also used in disorders of keratinization as icthyoses, palmoplanter keratoderma, PRP and lichen planus. • The dose ranges from 0.25: 1 mg/ kg per day. • It is best taken after a meal because it needs fat to be absorbed through the gut wall.
Isotretinoin: it is effective in severe and resistent forms of acne as nodulocystic acne and cases not responding to ordinary treatments. • Bexarotene: for cutaneous T cell lymphoma.
Side effects of retinoids: • The most serious is teratogenecity, so pregnancy should be absolutely prevented for at least 2-6 months after stoppage of the drug. • Headache,lethargy, anorexia, nausea and vomiting. • Benign intracranial hypertension (with isotretinoin). • Dryness of lips, nose and eyes. • Skeletal hyperostosis in prolonged therapy. • Elevation of liver enzymes. • Changes in serum lipids and elevation of triglycerides and cholesterol.