COFP Janmar Text

B I O T E R R O R I S M

PRINCIPLES AND PRACTICE OF DERMATOLOGY Dr Matthew Ng Joo Ming

INTRODUCTION DIAGNOSIS Medical schools and textbooks teach us The diagnosis of skin lesion is made by following dermatology by subjects such as eczema and the same general principle as in any branch of psoriasis. This is useful only for students who are medicine. The process begins by taking a history, new to dermatology. However, it has no use to the followed by a physical examination and if the practicing physician. Patient don’t come to you diagnosis is not made at this stage, further with a diagnosis but they come with a problem of investigations can be carried out. an unknown rash. HISTORY MORPHOLOGY OF SKIN LESION K Duration Characteristics morphology, pattern of K Relationship to physical agents: sun exposure, arrangement and lesions found in a particular occupation, and medication anatomical location can strongly suggest a certain K Puritis dermatological diagnosis. For example, group K Size and colour change vesicles on the penis strongly suggest a diagnosis K Family history of herpes simplex infection. A concise summation K Previous treatment of clinical features, including morphology of skin When describing skin lesion, the following should lesions, pattern of any eruption as well as symptoms be identified in turn: (e.g. itch), is helpful in arriving at a diagnosis. K Site and distribution: symmetrical, Consulting a good picture atlas of skin disease also asymmetrical aids clinical diagnosis. K Erythematous and non-erythematous Lesions can be grouped into four distinct K Surface characteristics: smooth, scaly, warty patterns: linear, annular, group and reticular. K Types of lesions: primary lesion _ macule, Some disorders by virtue of their etiology are papule, nodule, vesicle; secondary lesion _ localized to or limited to a particular area. Herpes erosions, ulcer, excoriation zoster occur in dermatomal pattern because the K Colour: pink, white, brown, yellow virus travel along the sensory nerve to the skin. K Borders and shape: well-defined, raised Hidradenitis affects the axillae and groin because borders, round, pedunculated it is a disorder of apocrine gland and the glands K Arrangement of lesions: linear, annular, group, are located densely in these areas. Photosensitive generalized, single dermatoses frequently affects the head, neck and K Special site: scalp, nails, mouth forearms since these areas are the sites of most intense sun exposure. Some disorders favour sites The acronyms below can be used to aid diagnosis of skin trauma, e.g. Vitiligo and psoriasis. of an unknown skin lesion in clinical practice: The table on the next page serves as an aid to D:distribution diagnosis when certain sites are involved. A:associated features M:morphology MATTHEW NG, MBBS(S’pore), Grad.Dip.Occ.Med, N:nature – special nature or character such as MMed(FM), MCFPS pain, pruritis, duration

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Region Common Uncommon

Face Erythematous patches Extensive actinic keratoses Contact dermatitis Seborrhoeic dermatitis Lupus erythematosus Atopic dermatitis Photodermatosis Fixed drug eruption

Pustular Acne vulgaris Tinea facicei Acne rosacea Perioral dermatitis

Butterfly rash Seborrhoeic dermatitis Lupus erythematosus Rosacea

Eyelids Seborrhoeic dermatitis Psoriasis Atopic dermatitis Periorbital dermatitis Contact dermatitis Angio-oedema Rosacea

Scalp - erythematosquamous Seborrhoeic dermatitis Discoid lupus erythematosus Psoriasis Tinea capitis Actinic keratoses - vesicular/pustular Staphylococcal folliculitis Acne vulgaris Seborrhoeic dermatitis Herpes zoster Infection Dermatitis herpetiformis

Trunk Drug exanthem Pityriais rosea Pityriasis vesicolor Tinea corporis Seborrhoeic dermatitis Mycosis fungoides Guttate psoriasis Scabies

Inguinal Intertrigo Contact dermatitis Seborrhoeic dermatitis Candidiasis Tinea curis

Axillae Intertrigo Candidiasis Seborrhoeic dermatitis Acantosis nigricans Contact dermatitis tinea

Upper limbs Atopic dermatitis Polymorphous light eruption Contact dermatitis Lichen planus Psoriasis Actinic keratosis Photodermatitis

Hands Actinic keratosis Lichen planus Pompholyx Tinea Scabies Palmar pustulosis Granuloma annulare Erythema multiformae Contact dermatitis

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Nails Psoriasis Tinea unguim Paronychia Dermatitis

Genitalia Seborrhoeic dermatitis Lichen planus Scabies Fixed drug eruption Candidiasis Secondary syphilis Psoriasis Contact dermatitis

Natal cleft Intertrigo Candidiasis Tinea Seborrhoeic dermatitis Psoriasis Scabies

Submammary Intertrigo Psoriasis Candidiasis Seborrhoeic dermatitis

Lower legs Stasis dermatitis Vasculitis Contact dermatitis Necrobiosis lipoidica Folliculitis Psoriasis Atopic dermatitis Lichen simplex chronicus

Feet Tinea Psoriasis Pompholyx Contact dermatitis

Generalized rash Atopic dermatitis Psoriasis Drug eruption Erythroderma of other causes Exanthem

COMMON SKIN CONDITIONS 2. Acne: comedonal, inflammatory, cystic To be diagnosed at first visit. 3. Urticaria; acute, chronic, anaphylaxis To be diagnosed by primary care physician. 4. Viral infections – common: herpes simplex infection, herpes zoster, chicken pox, viral 1. Eczema/Dermatitis: atopic eczema, warts, molluscum seborrhoeic eczema, discoid eczema, xerotic 5. Bacterial infections – common: folliculitis, eczema, stasis eczema, lichen simplex furuncle, carbuncle, impertigo, ecthyma, chronicus, irritant contact dermatitis, cellulitis eryspalis, necrotising faciatis allergic contact dermatitis, photodermatitis, 6. Psoriasis: guttate, plaque, erythrodemic, airborne contact dermatitis. pustular

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7. Fungal infection: tinea versicolor, The mainstay of dermatological treatment is dermatophytosis (skin, hair, nail), candidiasis TOPICAL THERAPY. It is employed to deliver (skin, nails) active ingredients to the skin, either at the stratum 8. Parasitic infections: scabies, pediculosis corneum or via percutaneous absorption into the (capitis, corporis, pubic), cutaneous larva dermis and appendage areas, to provide a protective migrans barrier, or hydrate and moisturized. 9. Antropod bite reactions Ingredients such as powders: zinc oxide, starch, 10. Drug eruptions: localized (fixed drug calamine; liquids: water, alcohol, glycol; oils, eruption), generalized ( exantham ), Blistering, greases or waxes are combined to produced urticaria ointments, gels creams, powder, lotions, tintures and pastes. These vehicles are used to deliver drugs Associated Systemic Symptoms – in topical therapy. Signs and symptoms The vehicle is the key factor in the effectiveness of therapy. Factors that influence the therapeutic Common urgent Common Non Urgent outcome are water/lipid miscibility, occlusive Acute Dermatitis Chronic dermatitis properties and durability. Water soluble drugs are Cystic Acne Mild Acne delivered more effectively by aqueous vehicles such Urticaria – angioedema Viral Herpes Zoster Warts as aqueous creams, gels and lotions. Similarly, lipid Herpes simplex soluble drugs are best delivered by oily creams and Chicken pox ointments. Pastes and ointments are occlusive, Bacterial – all Folliculitis increasing the temperature of the skin and thus Parasitic – all Fungal Erythrodemic Psoriasis Plaque Psoriasis increasing the percutaneous absorption of the Pustular Psoriasis active ingredients. Gels, ointments and pastes are Drug Eruption Anthropod Bite more durable than creams and lotions and hence, Uncommon Urgent / Important their duration of action is longer. 1. Blistering conditions – TEN, EM, Pemphigus, Phemhigoid In general, CREAMS (an emulsion of ointment 2. Oral Ulcers – Acute and water) with an aid of an emulsifying agent, 3. Photodermatitis 4. Purpuric Painful lesion – vasculitic are generally used on normal or moist skin. They 5. Cancers – Melanoma, Squamous cell ca are cosmetically acceptable to used on the face, for 6. Rash with fever 7. Leprosy use in the flexures and for application to large areas. However, some creams can be drying if the skin is already very dry. Preservatives used in creams can THERAPEUTICS cause contact dermatitis in some patients. The aims of treatment in any skin lesion are: 1. Clear symptoms OINTMENTS consist of organic hydrocarbons, 2. Prevent spread alcohol and acids with little or no water, are used 3. Clear the lesions when the skin is dry and when enhanced 4. Prevent relapse absorption is required. Ointments are generally 5. Prevent complications more effective than creams.

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LOTIONS are used on wet surfaces e.g. wet rashes steroid preparations have similar properties and (soaks or wet dressings), on hairy areas (scalp, differ only in strength, base and cost. They are axillae and pubic area) and oral mucosa divided into seven classes (Class 1: most potent (mouthwashes). – Class 7: mild), depending on their ability to induce vasoconstriction of the small vessels in GELS are used as an alternative to lotions in hairy the upper dermis. In practice, however, it is areas and where a drying effect is beneficial, impossible and impractical to remember such a especially gels with an alcoholic base e.g. in acne. classification. It is more convenient and practical Gels and lotions with alcohol should not be applied to divide it just into three classes: to excoriated or abraded skin, as they will sting. 1. Strong: Dermovate, Diprocel PASTES are used for occlusions and protection, 2. Normal: Cutivate, betnovate, celestoderm and where substantiative effects are required, 3. Mild: Eumovate, hydrocortisone allowing the drug to stay in contact with the skin For the same steroid ingredient, the for prolong periods. They are also used in the formulation and the strength of the application of an irritant drug to a limited area of pharmacological agent can also influence its skin, e.g. dithranol, high concentration of salicylic ability to induce vasoconstriction and hence its acid. classification. E.g. ¼ strength celestoderm can PAINTS are liquid preparations that dry rapidly be considered a weak steroid. once applied to the skin. They are useful for application to small localized areas of the skin and CHOICE OF TREATMENT for rapidly delivering the active ingredient to areas 1. Effectiveness/efficacy with skin folds such as between toes, the groin and 2. Safety under the breasts. 3. Cost DUSTING POWDERS consist of powders such 4. Convenience. as talcum, zinc oxide and starch. They are useful in intertriginous areas to separate apposed skin surfaces and enhanced evaporation. However, they FAILURE OF TREATMENT may not be as effective as other bases in delivering Why patient did not get better? the active ingredient to the site of action. 1. Inadequate clearance: poor understanding of topical treatment TOPICAL STEROIDS 2. Failure to identify and remove irritants and Topical steroids are the most effective aggravating factor medications for treating inflammatory skin 3. Lack of social, economic and psychological disease. They are safe when used properly. All support.

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