Skin

Published on 16/03/2015 by admin

Filed under Basic Science

Last modified 16/03/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 1270 times

chapter 42 Skin

The skin, the skin

’Tis a wonderful thing.

Keeps the outside out

And the inside in.

INTRODUCTION AND OVERVIEW

The skin is the most obvious organ in the body and every practitioner sees lots of it—about two square metres of it walks through the door with each adult patient. Skin is our interface with the environment and it always tells us things about the patient.

Every primary practitioner sees a wide variety of skin diseases in patients of all age groups, including eczema, psoriasis, infections, acne, urticaria, various pigmented lesions and solar damage including skin cancer. Up to 15% of general practice presentations are for skin conditions.

The skin can itch, burn, swell and appear unsightly, and this can frequently lead to anxiety or psychological reactions. The skin presents to the world and even an apparently trivial skin blemish may be considered a major problem by the patient. Many skin conditions can also cause such persistent discomfort and inconvenience in day-to-day living that patients feel restricted, even in the most basic of activities, resulting in loss of confidence, low self-esteem and diminished quality of life.

The more skin conditions can be understood and managed in relation to the patient’s general health, the more likely there is to be a cure, sustained relief or benefit to the patient as a whole.

This chapter is too brief to give a comprehensive coverage of skin disease. Instead, it provides a framework to enable a clinician to approach skin conditions from an integrative perspective, using some common conditions as examples. Some skin conditions are covered at greater length, with integrative approaches, while others have been included only briefly, to represent what is common in primary care practice.

As in other areas of medicine it is important to ensure that both diagnosis and treatment of skin conditions address causes, rather than suppressing symptoms alone. Skin conditions often have multiple contributing causes, including topical influences, autoimmune or genetic susceptibility, food factors and numerous ancillary triggers.

AETIOLOGY

Many people have a predisposition to skin disease before triggers or precipitating events cause the condition to appear. Allergic or autoimmune predisposition, dry skin, excessive sun exposure, stress or nutritional deficiencies can all set the scene. The triggers may include infection (bacteria, fungi, yeasts, viruses, parasites) or trauma, leading to inflammation or neoplastic change. There are also systemic diseases that have skin manifestations, such as diabetes, thyroid disease, high lipids, and deficiencies including fatty acids, zinc, iron and B vitamins.

DIAGNOSIS

While diagnosis of many skin conditions relies on pattern recognition, sometimes it is elusive. A well-honed systematic approach is essential for diagnosis.

Systematic steps:

1. History
2. Examination
3. Accurate description of lesions or skin
4. Differential diagnosis
5. Special tests
6. Diagnosis
7. Treatment plan.

• History—in addition to the history of the condition, questions relating to general health are also needed. Past medical history, family history, allergic history, a nutritional assessment, including supplements, and medications are all important. Listen to patients, as they often have perceptions about their skin and ideas that provide clues to the causes or triggers for the condition.
• Examination

• Dermatology is a visual branch of medicine, and in order to ensure accurate diagnosis, examination requires a bright light and good magnification.
• Dermoscopy is a valuable examination tool for pigmented lesions. An ultraviolet Wood’s lamp can cause fungal infections and erythrasma to fluoresce.
• Examine the whole skin in addition to the specific lesion. Have a good look—touch, stretch and feel the texture and thickness.

• Accurate description of lesions or skin—an accurate description (Table 42.1) requires careful observation and often leads directly to the diagnosis. A dermatology atlas and comprehensive text are helpful.
• Special tests—take the time and make the effort to do the tests. Investigations are:

• swabs, skin scrapings or nail clippings
• punch, shave or incisional biopsy. These are simple procedures that take little extra time and often make or confirm a diagnosis. It is important to provide a brief clinical outline, a description of the lesion and, if possible, a differential diagnosis for the histopathologist, as microscopic appearances can be equivocal.

• Diagnosis will arise from the above systematic approach. Remember that the skin is a reflector of systemic conditions.

TABLE 42.1 Terminology of lesions

image

TREATMENT PLAN

Each skin condition requires specific treatment measures. In general, however, integrated management could include the following:

• Prevention—where triggers are identifiable; for example, avoidance of arginine-rich foods (peanuts, almonds and chocolate) with herpetic infections; management of sun exposure to minimise solar sun damage while ensuring adequate sun exposure to manufacture vitamin D in the skin.
• Surveillance—Hippocrates said to ‘Make a habit of two things—to help or at least to do no harm’. The positive diagnosis of benign or self-limiting conditions such as pityriasis rosea, keratosis pilaris, granuloma annulare or toxic viral rashes is important, as they often require no intervention.
• Self-help and general remedies that aim to improve the patient’s general health and benefit the condition. For example:

• Reduce exposure to heat, spices or alcohol with rosacea.
• Reducing immune stressors can reduce the threshold to autoimmune disease that affects or reflects in the skin. These diseases include vitiligo, melanoma, halo naevus, idiopathic thrombocytopenic purpura, Hashimoto’s thyroiditis, systemic lupus erythematosus, scleroderma and diabetic skin disease. Stressors that reduce a patient’s adaptive capacity include emotional stress (including anxiety and depression), chemical load, allergic load, hormonal imbalance, fatigue, endocrine disease, chronic viral infections and nutritional deficiencies (zinc, iron, vitamin D, vitamin B12 or folic acid). These stressors are common and need to be addressed.

• Pharmacological relief is important—a teenager with severe acne can try multiple nutritional and topical measures but needs treatment with a high probability of a rapid response. This will often include topical as well as oral treatments.
• Surgical excision is still the treatment of choice for the majority of skin cancers. Excision provides a specimen, which is always sent to pathology. The dermatopathologist will confirm or make the diagnosis and establish the presence of a margin of safety around the malignant lesion.

IMPORTANT PITFALLS IN SKIN MANAGEMENT

• Remember to take skin conditions seriously. Most are not fatal but many cause angst and suffering, or low mortality with high morbidity. Take the trouble to assess the impact of the condition on the patient. For example, most young people with moderate acne experience significant loss of confidence, depression or even difficulty gaining employment.
• Work for a positive diagnosis before committing to long-term treatment. For example, is it psoriasis, eczema or fungal?
• Do not use fluorinated steroids on the face, especially around the mouth.
• Do not use steroids on rashes where there could be fungal infections as this can lead to extension of the infection, known as tinea incognito.

SPECIFIC SKIN CONDITIONS

In order to see how a well-honed systematic approach can be applied in practice, we will look at the management of some specific skin conditions. Some of these conditions are well managed using an integrative approach and are discussed more fully. Others require standard medical treatment alone, and many of these are covered only briefly, in order to provide a more representative picture of skin presentations.

ECZEMA

Eczema is the most common skin reaction. It is an inflammatory disorder and the term is interchangeable with dermatitis, although sometimes ‘dermatitis’ is used when the cause is external or exogenous (Box 42.1).

BOX 42.1 Classification of eczema

Contact or exogenous eczema

• irritant contact eczema (90%)
• allergic contact eczema
• photosensitive

Constitutional or endogenous eczema

• atopic
• pompholyx (dyshidrotic)
• hyperkeratotic

• discoid or nummular
• asteatotic or eczema craquelé
• seborrhoeic eczema of adults or infants

Contact or exogenous eczema

• Irritant contact—occurs whenever irritant materials are in prolonged contact with the skin. This is not an allergy and does not reflect individual sensitivity. It is a direct irritant effect of substances such as detergent, petrol or solvents. Irritant contact dermatitis of the hands is the most common occupational disease.
• Allergic contact—occurs when there is an allergic reaction to an agent in contact with the skin (Box 42.2). There are many causes. These may be suspected from the history and confirmed by patch testing if necessary.
• Photosensitive dermatitis is eczema in light-exposed areas, often as a side effect of a drug.
• Napkin dermatitis is a specific form of irritant contact dermatitis following prolonged contact with urine and faeces.
• Plant contact dermatitis.

BOX 42.2 Common contact allergens

• adhesives
• antibiotic
• cement, leather, matches
• chromates
• cosmetic preservatives, laboratories, white shoes, deodorants
• cosmetics, creams containing lanolin
• cosmetics, soaps
• epoxy resin
• formaldehyde
• fragrances/perfume mix
• gloves, shoes, elastic straps, tyres
• jewellery, watch straps, jean studs, coins, tools
• lignocaine
• neomycin
• nickel
• parabens
• preservative
• rubber chemicals
• topical local anaesthetic
• wool alcohols

Constitutional or endogenous eczema

• Atopic eczema (see next section)
• Pompholyx or dyshidrotic eczema—this is a common hand or foot eczema characterised by small blisters on the palms or soles, especially at the margins, that burst and heal with peeling. Because the skin is thick, inflammatory fluid is trapped in the skin, leading to this characteristic appearance. A potent topical steroid ointment is required.
• Hyperkeratotic eczema
• Discoid or nummular eczema—the pattern of one or more oval or coin-shaped plaques of eczema is characteristic. The cause is unknown but lesions may occur on any part of the body, particularly on the legs.
• Asteatotic eczema or eczema craquelé—a dry and itchy form of eczema on the legs that produces a ‘crazy paving’ type of appearance. It is related to dry skin (xerosis) and is common later in life.
• Seborrhoeic eczema—a red, itchy, scaling rash that commonly affects the scalp and midline areas of the face, including around the nose and between the eyebrows. The ears may also be involved, and occasionally areas on the central chest and axillae are affected. It is thought to be caused by sensitivity to a yeast, Malassezia. The eyelids often have scales and redness (blepharitis).

Patients often notice that seborrhoeic eczema is worse when they are tired, run-down or eating excessive sugar or refined carbohydrates. Yeasts feed on sugar.

Management is most effective when anti-yeast shampoos or creams are combined with a diet that avoids sugar and refined or high-GI carbohydrates.

• Infantile seborrhoeic eczema—affects newborns up to 6 months of age, manifesting as cradle cap, napkin dermatitis or sometimes spreading over the whole trunk.

Atopic eczema

Atopic eczema is dealt with in detail here, as it is a good example of how a practitioner can make a great contribution to the wellbeing of the patient and their family, by employing integrative principles. This discussion emphasises management in children, where atopic eczema is most common, but the principles can be adapted to all age groups.

Atopic eczema is common, often very itchy and usually begins in young children from allergic families. Atopic patients have an allergic predisposition to asthma, eczema, hay fever, urticaria and other allergies. It is important to spend time with the patient, collecting information and piecing together the puzzle. Patients or parents will tell you the answers if you ask and listen. Avoid reflex prescriptions for medications, including nutritional supplements.

Atopic eczema can be likened to a slow-burning scrub fire. It is much more than a steroid-responsive dermatosis. Each patient needs to be managed with an appreciation of the causes, triggers and individual patterns of their disease.

The prevalence of atopic eczema and allergic disease has increased dramatically over the past three decades. One theory put forward to explain this is the ‘hygiene hypothesis’, which argues that early childhood exposure to infections inhibits the tendency to develop allergic disease. The idea behind this hypothesis is that bacterial and viral infections during childhood somehow ‘tone up’ the immune system and thereby reduce the tendency to develop allergic disease. Children in Western societies have a more hygienic and ‘sanitised’ lifestyle and a greater risk of developing allergic illness. The increasing prevalence of autoimmune disease may be related.

The cause of atopic eczema is probably multifactorial: genetic, immunological and environmental.

Other predisposing factors to be considered may include a family history of allergies, early introduction of cow’s milk or wheat, and of antibiotics (beta-lactam), vaccinations (pertussis, influenza), dust mite or cockroach exposure, a smoking parent and stress.

Atopic eczema will resolve in at least half of children by the age of five, but a significant number will go on to develop asthma. Atopic eczema is a T helper 2 (Th2) dominant disease.

Clinical presentation

Commencing around 3 months of age, atopic eczema is characterised by dryness, itching and scaling. The rash is usually symmetrical and commences on the cheeks and flexures. There is often subsequent excoriation and lichenification from scratching.

Assessment

A detailed history should be taken, including suspected allergies, details of the diet and preparations used to treat the skin. The family will usually have suspicions about factors thaat may be contributing, and clues will emerge about foods or general triggers. These families have a child with a chronic disease that requires ongoing monitoring, considerable thought and a lot of care each day. The impact on the family as a whole needs to be appreciated.

Food sensitivity is more likely to be a factor in childhood eczema than in adults, and parents will often ask about this. Features in the history that suggest food intolerance as more probable than inhalant allergy include: early age of onset; past history of atopic disease; infective pattern to asthma; sinusitis, otitis media, glue ear or grommets; associated symptoms relating to other systems, such as irritable bowel syndrome, migraine, fatigue, behaviour problems in children; recurrent croup; positive family history of food problems; negative skin tests for inhalants; and a poor response to drug therapy.

Children tend to react to foods that they eat frequently or crave. Wheat, potato, tomato, cows’ milk and citrus are common food sensitivities that may contribute to eczema.

Sometimes skin testing for inhalant allergens, and particularly for those that can be avoided, such as house dust mite, cat or dog, can be useful. Radioallergosorbent test (RAST) is an alternative technique with blood testing to test for IgE-mediated allergies.

Most food sensitivity is not IgE mediated, and skin or blood testing (IgE or IgG) is not reliable in excluding food problems. The most accurate way of diagnosing food sensitivities is through food elimination and challenge dietary testing.

Prevention

(See also Ch 55, Child health and development.)

• Pregnant mothers with a family history of atopy or allergies should have their diet discussed. Avoidance of specific foods such as egg white or shellfish in pregnancy may reduce the risk of atopic disease in the baby, but there should also be discussion of the patient’s food intake to ensure that there is a good variety of foods and moderation of intake of foods where there has been a family problem.
• A good level of antioxidant intake during pregnancy reduces allergic disease in the first 2 years of life.
• Breastfeeding should be encouraged, as this is protective of the infant’s immunological health.

And for all age groups:

• Avoid known or suspected allergens, to reduce the allergic load on the individual.
• Minimise exposure to potentially toxic or sensitising chemicals in the environment. These include petrochemicals, pesticides, deodorisers, aldehydes, solvents and other volatile organic chemicals.

Treatment

These approaches are directed towards young children, but are adaptable to all age groups.

• Once a young child has atopic eczema, reducing dust in the bedroom and removing pets and feathers are precautionary measures.
• Reduce trigger factors, including woollen clothes in contact with the skin.
• Avoiding contact with skin infections, especially cold sores or herpetic infections, helps to prevent infections that cause more severe eruptions in eczematous skin.
• Treat dry skin—like dry leather, dry skin does not respond well to soaps or detergents, and needs oil or moisturising preparations to keep it soft and healthy. How well would leather shoes respond to regular washing with soap and hot water? Similarly, eczematous skin is best cleansed with cooler water and minimal use of a soap substitute or cream.
• Emollients or moisturisers are useful for greasing dry skin (xerosis). Although many commercial brands have petrochemical bases, they usually work well in practice. Often these base preparations have added ingredients such as oils or colloidal oatmeal. Plant oils can also be useful topically, and include evening primrose, vitamin E, rosehip and coconut oils. Emollients soak into the skin within 2 hours and need to be used frequently to moisturise the skin effectively. These oils can also be applied as ointments or creams. Creams contain water and therefore also preservatives, which have the potential for sensitisation. The more greasy the emollient the more effective, but often also the less cosmetically acceptable.
• Ensure there are adequate oils in the diet. Fish oil (adult dose 1000 mg caps, four daily) or flaxseed oil (especially for vegetarians), which is a comparable omega-3 fatty acid. Omega-6 fatty acids such as evening primrose oil can be used in smaller doses and also applied topically as an emollient. Dietary olive oil can be used for dressings, salads and cooking.
• Infection is important in atopic eczema. Up to 80% of eczema is colonised by pathogenic bacteria, especially Staphylococcus aureus. The more severe the dermatitis, the denser the infection. S. aureus causes direct irritation or exotoxin immunological sensitisation. Bacteria belong on the outside of the skin but in eczema they readily penetrate the skin, causing inflammation and itching. Scratching then ploughs in more bacteria. Antiseptic measures or topical antibiotics can help eradicate infection and aid repair of the barrier function of the skin.

Infection control measures in atopic eczema:

• Condy’s crystals (KMnO4)—1:8000 solution gives a light-pink solution in the bath and is a safe and effective antiseptic
• other antiseptics in the bath water—these include triclosan and benzalkonium chloride in oil
• calendula cream3—has antiseptic properties for topical use
• topical antibiotic—(e.g. mupirocin ointment) for established localised bacterial infection
• oral antibiotics—for more widespread or severe local infection.

• Anti-inflammatory agents such as topical corticosteroid ointments or pimecrolimus cream (for the face) reduce inflammation and restore the barrier function of the skin, moisture and normal texture.
• Know the forms and doses of topical medications. Common forms: ointments are oil in oil, creams are oil in water, and lotions contain still more water.
• Different potencies of topical corticosteroids are used for different areas and age groups. Use only hydrocortisone on the face, and only the more potent fluorinated topical corticosteroids on the hands and feet where the skin is thick. Hydrocortisone can be effective on the trunk and limbs in children.
• Non-steroidal pimecrolimus cream can be useful, especially on the face.
• How much ointment will be needed? To work out the dose needed, use the ‘rule of hand’ (Fig 42.1).4 Four hand areas (using the area under the flat of the hand) requires one gram of ointment per treatment. For example, if ointment is being used daily over eight hand areas, this is 2 grams daily, and a 15-gram tube will last 1 week. It is important to prescribe an adequate quantity to last until the next review.
• Put out the fire. Cool down the inflammation of eczema. Eat, drink, dress, sleep, bathe, shower and think cool. Inflammatory conditions are like a grass fire—easier to prevent than to put out. Turning down the central heating, avoiding heating foods such as spices, sleeping and dressing cool, bathing or showering cool and keeping a cool head, all help. Traditional Chinese medicine incorporates concepts of heat in diagnosis and treatment.
• Nutritional supplements:

• omega-3 fatty acids—replace arachidonic acid and lead to reduced levels of inflammatory mediators and IgE. Sources are:

image deep-sea cold water fish such as salmon, sardines, herrings, mackerel or fish oil capsules 1000 mg (adult dose: four daily)
Buy Membership for Basic Science Category to continue reading. Learn more here

Related posts:

Default ThumbnailDetoxification Default ThumbnailThe general check-up Obesity Respiratory medicine Men’s health Herb–drug interactions