Eczema

Dermatology lec

1. ECZEMA 20% of all new patients referred to clinics 

2. Terminology The word ‘eczema’ comes from the Greek for ‘boiling’ – a reference to the tiny vesicles (bubbles) that are often seen in the early acute stages of the disorder ‘Dermatitis’ means inflammation of the skin and is therefore, strictly speaking, a broader term than eczema

3. Classification

4. Classification

5. Histology In the acute stage, oedema in the epidermis ( spongiosis ) progresses to the formation of intra-epidermal vesicles, which may coalesce into larger blisters or rupture. The chronic stages of eczema show less spongiosis and vesication but more thickening of the prickle cell layer ( acanthosis ) and horny layers (hyperkeratosis and parakeratosis ). variable degree of vasodilatation and infiltration with lymphocytes

6. The sequence of histological events in eczema

7. The causes of eczema

8. Clinical appearance The absence of a sharp margin is a particularly important feature that separates eczema from most papulosquamous eruptions . Acute eczema Acute eczema is recognized by its: weeping and crusting blistering – usually with vesicles but, in fierce cases, with large blisters redness, papules and swelling ill-defined border and scaling   Chronic eczema Chronic eczema may show all of the above changes but in general is: less vesicular and exudative more scaly, pigmented and thickened; more likely to show lichenification – a dry leathery thickened state, with increased skin markings, secondary to repeated scratching or rubbing; and more likely to fissure

9. Complications Heavy bacterial colonization is common in all types of eczema , overt infection is most troublesome in the seborrhoeic , nummular and atopic types. Local superimposed allergic reactions to medicaments can provoke dissemination, especially in gravitational eczema . a huge effect on the quality of life. An itchy sleepless child can wreck family life. Eczema can interfere with work, sporting activities and sex lives. Jobs can be lost through it

10. Differential diagnosis Papulosquamous dermatoses , such as psoriasis or lichen planus , are sharply defined and show no signs of epidermal disruption Always remember that eczemas are scaly, with poorly defined margins. eczemas exhibit features of epidermal disruption such as weeping, crust, excoriation, fissures and yellow scale (because of plasma coating the scale ). Once the diagnosis of eczema becomes solid, look for clinical pointers towards an external cause. This determines both the need for investigations and the best line of treatment. A contact element is likely if: there is obvious contact with known irritants or allergens the eruption clears when the patient goes on holiday , or at the weekend the eczema is asymmetrical , or has a linear or rectilinear configuration the rash picks out the eyelids, external ear canals, hands and feet, the skin around stasis ulcers, or the perianal skin.

11. Investigations Exogenous eczema Patch testing to confirm allergic contact dermatitis and to identify the allergens responsible for it In patch testing, standardized non-irritating concentrations of common allergens are applied to the normal skin of the back. If the patient is allergic to the allergen, eczema will develop at the site of contact after 48–96 h. Patch testing with irritants is of no value in any type of eczema Photopatch testing A chemical is applied to the skin for 24 h and then the site is irradiated with a suberythemal dose of ultraviolet irradiation; the patches are inspected for an eczematous reaction 48 h later.

12. Other types of eczema The only indication for patch testing here is when an added contact allergic element is suspected. This is most common in gravitational eczema   Prick testing in atopic eczema Total and specific IgE antibodies are measured by a radio- allergosorbent test RAST test as it carries no risk of anaphylaxis, is easier to perform and is less time consuming Cultures for bacteria and Candida if the eczema is worsening despite treatment, or if there is much crusting

13. Acute weeping eczema treatment rest and liquid applications Weeping eczema of the hands or feet is to use thrice daily 10-min soaks in a cool 0.65% aluminium acetate solution – saline or even tap water will do almost as well each soaking being followed by a smear of a corticosteroid cream or lotion and the application of a non-stick dressing or cotton gloves One reason for dropping the dilute potassium permanganate solution that was once so popular is because it stains the skin and nails brown Wider areas on the trunk respond well to corticosteroid creams and lotions or traditional remedies such as calamine lotion, and the use of half-strength magenta paint for the flexures are also effective

14. Wet wrap dressings This is a labour -intensive but highly effective technique, of value in the treatment of troublesome atopic eczema in children. After a bath, a corticosteroid is applied to the skin and then covered with two layers of tubular dressing – the inner layer already soaked in warm water, the outer layer being applied dry and the dressings can then be left in place for several hours The evaporation of fluid from the bandages cools the skin and provides rapid relief of itching

15. Subacute eczema treatment Steroid lotions or creams are the mainstay of treatment bacitracin , fusidic acid,mupirocin or neomycin can be incorporated into the application if an infective element is present, but watch out for sensitization to neomycin, especially when treating gravitational eczema

16. Chronic eczema treatment S teroids in an ointment base, cause best responds, but is also often helped by non-steroid applications such as ichthammol and zinc cream or paste The strength of the steroid is important Nothing stronger than 0.5 or 1% hydrocortisone ointment should be used on the face or in infancy. In adults one should be reluctant to prescribe more than 200 g/week of a mildly potent steroid, 50 g/week of a moderately potent or 30 g/week of a potent one for long periods Calcineurin inhibitors such as tacrolimus and pimecrolimus work well, although they lack the potency of strong topical corticosteroids. Systemic antibiotics for bacterial superinfection or incorporation of antibiotics (e.g. fusidic acid, mupirocin , neomycin or chlortetracycline) or antiseptics (e.g. Vioform ) into the steroid formulation S alicylic acid (1–6% in emulsifying ointment) or stabilized urea preparations for chronic localized hyperkeratotic eczema of the palms or soles

17. Systemic treatment Short courses of systemic steroids may occasionally be justified in extremely acute and severe eczema, particularly when the cause is known and already eliminated (e.g. allergic contact dermatitis). However, prolonged systemic steroid treatment should be avoided in chronic cases, particularly in atopic eczema. Antihistamines may help at night. Systemic antibiotics may be needed in widespread bacterial superinfection . Staphylococcus aureus routinely colonizes all weeping eczemas, and most dry ones as well

18. Common patterns of eczema

19. Irritant contact dermatitis This accounts for more than 80% of all cases of contact dermatitis, and for the vast majority of industrial cases Cause Strong irritants elicit an acute reaction after brief contact but prolonged exposure, sometimes over years, is needed for weak irritants to cause dermatitis Detergents, alkalis, solvents, cutting oils and abrasive dusts are common culprits. Past or present atopic dermatitis doubles the risk of irritant hand eczema developing

20. Complications The condition may lead to loss of work . Differential diagnosis It is often hard to differentiate irritant from allergic contact dermatitis, and from atopic eczema of the hands   Investigations Patch testing with irritants is not helpful and may be misleading but patch testing to a battery of common allergens help to detect allergic element   Treatment based upon avoidance of the irritants reduced exposure by the use of protective gloves and clothing. Moderately potent topical corticosteroids and emollients are valuable Prevention is better than cure because, once started, irritant eczema can persist long after contact with offending substances has ceased, despite the vigorous use of emollients and topical corticosteroids

21. Allergic contact dermatitis Cause The mechanism is that of delayed (type IV) hypersensitivity, It has the following features. Previous contact is needed to induce allergy. It is specific to one chemical and its close relatives. After allergy has been established, all areas of skin will react to the allergen. Sensitization persists indefinitely. Desensitization is seldom possible

22. Allergens Are variable Their ability to sensitize varies – from substances that can do so after a single exposure (e.g. poison ivy) to those that need prolonged exposure (e.g. chrome – bricklayers take an average of 10 years to become allergic to it). Presentation and clinical course Allergic contact dermatitis should be suspected if: 1. certain areas are involved (e.g. the eyelids, external auditory meati , hands or feet, and around gravitational ulcers) 2. there is known contact with the allergens mentioned 3. the individual’s work carries a high risk (e.g. hairdressing, working in a flower shop, or dentistry)

23. Investigations Patch testing Some allergies are more common than others, nickel top of the list, with a positive reaction in some 15% of those tested; fragrance allergy usually comes second. It is important to remember that positive reactions are not necessarily relevant to the patient’s current skin problem; some are simply ‘immunological scars’ left behind by previous unrelated problems Treatment avoidance of the relevant allergen is most important, Job changes are sometimes needed Reducing exposure is usually not enough Topical corticosteroids give temporary relief

24. Occupational dermatitis Dermatitis is the second most common occupational disorder – second only to musculoskeletal injuries The hands are affected in 80–90% of cases. Often several factors (constitutional, irritant and allergic) have combined to cause this

25. Atopic eczema

26. Atopic eczema The word ‘ atopy ’ comes from the Greek ( a- topos meaning ‘without a place’). Atopy is a state in which an exuberant production of IgE occurs as a response to common environmental allergens. Atopic subjects may, or may not, develop one or more of the atopic diseases such as asthma, hay fever, eczema and food allergies Several environmental factors that reduce the risk of developing atopic disease are: having many older siblings, growing up on a farm, having childhood measles and gut infections.

27. The ‘hygiene hypothesis’ blaming the early use of antibiotics and a reduced exposure to orofaecal and other infections for preventing normal immunological maturation and shifting the circulating T lymphocytes of children destined to develop allergies from a Th1 to a Th2 response. Perinatal administration of a Gram-positive probiotic ( Lactobacillus GG) to infants at risk of atopic disease significantly reduces the incidence of eczema for up to 4 years. Unfortunately, no such benefit is seen following administration to older children or adults.

28. Inheritance A strong genetic component is obvious, although affected children can be born to clinically normal parents. The concordance rates for atopic eczema in monozygotic and dizygotic twins are around 80% and 22%, respectively Atopic diseases tend to run a specific type within each family. In some, most of the affected members will have eczema; in others, respiratory allergy will predominate. There is also a tendency for atopic diseases to be inherited more often from the mother than the father , and if both parents have atopic eczema, a child has a 75% chance of developing the disease. Loss of function in the filaggrin gene causes ichthyosis vulgaris but is also strongly predictive for atopic eczema.

29. Presentation and course It affects at least 3% of infants Onset 75% of cases of atopic eczema begin before the age of 6 months, and 80–90% before the age of 5 years. the onset may be delayed until childhood or adult life. Some 60–70% of children with atopic eczema will clear by their early teens, although subsequent relapses are possible.

30. Lesions The distribution and character of the lesions vary with age but a general dryness of the skin may persist throughout life. In infancy atopic eczema tends to be vesicular and weeping often starts on the face with a non-specific distribution elsewhere, commonly sparing the napkin (diaper) area . In childhood the eczema becomes leathery, dry and excoriated affecting mainly the elbow and knee flexures, wrists and ankles . A stubborn ‘ reverse ’ pattern affecting the extensor aspects of the limbs is also recognized. In adults the distribution is as in childhood with a marked tendency towards lichenification and a more widespread but low-grade involvement of the trunk, face and hands. White dermographism , is often striking, but not diagnostic of atopic eczema.

31. The cardinal feature of atopic eczema is itching , and scratching may account for most of the clinical picture. Affected children may sleep poorly , be hyperactive and sometimes manipulative, using the state of their eczema to get what they want from their parents. The condition remits spontaneously before the age of 10 years in at least two-thirds of affected children, but it may come back at times of stress. Eczema and asthma may seesaw, so that while one improves the other may get worse.

32. Diagnostic criteria

33. Complications Overt bacterial infection Viral infections, most dangerously with widespread herpes simplex (eczema herpeticum ), but also with molluscum contagiosum and warts. Growth impairment because of impaired sleep due to itching and absorption of topical steroids can contribute Investigations   The value of prick testing in atopic eczema remains controversial. Often the finding of multiple positive reactions, and a high IgE level, does little more than support a doubtful clinical diagnosis.

34. Treatment Explanation , reassurance and encouragement. Avoidance of exacerbating factors such as irritants (e.g. woollen clothing next to the skin) and avoid extremes of temperature, and contact with soaps and detergents . Emollients used regularly. Those with an associated ichthyosis should generally use ointments rather than creams. O cclusive bandaging to cut the scratch–itch cycle by ( e.g. with a 1% ichthammol paste bandage). Nails should be kept short.

35. Topical steroids . A technique useful for extensive and troublesome eczema, particularly in children, is that of ‘ wet wrap’ dressings Tacrolimus is an immunosuppressant, now available as an ointment for topical use in eczema unresponsive to conventional therapy. The 0.1% ointment is equivalent in strength to a moderate or potent topical corticosteroid but without the potential to cause skin atrophy Best used for treatment of resistant eczema on sensitive sites, such as the face, or in patients requiring constant use of topical steroids. Local infection might be troublesome and concerns remain about the development of skin cancer or lymphoma in the long term. Patients should be advised to avoid excessive exposure to sunlight or UV lamps while using tacrolimus .

36. Sedative antihistamines (e.g. trimeprazine or hydroxyzine ) are of value if sleep is interrupted, but histamine release is not the main cause of the itching, so the newer non-sedative antihistamines help less than might be expected. Antibiotics Acute flares are often induced by the surface proliferation of staphylococci, even without frank sepsis. A month’s course of a systemic antibiotic (e.g. erythromycin) may then be helpful. Allergen avoidance as house dust mites, sometimes, but not always, measures to reduce contact with these allergens help eczema. These measures should include encasing the mattress in a dustproof bag, washing the duvets and pillows every 3 months at a temperature greater than 55°C, and thorough and regular vacuuming in the bedroom, where carpets should preferably be avoided .

37. Do not keep pets to which there is obvious allergy. The role of diet in atopic eczema is debatable, and treatments based on changing the diet of patients are often disappointing. It is not certain that the avoidance of dietary allergens (e.g. cow’s milk and eggs) by a pregnant or lactating woman lessens the risk of her baby developing eczema. It may still be wise to breastfeed children at special risk for 6 months

38. Routine inoculations are permissible during quiet phases of the eczema. However, children who are allergic to eggs should not be inoculated against measles, influenza and yellow fever. Those with active herpes simplex infections should be avoided to cut the risk of developing eczema herpeticum In stubborn cases: UVB, UVA-1 (340–400 nm) or even PUVA Ciclosporin Azathioprine Other Chinese herbal remedies

39. Seborrhoeic eczema Presentation and course mainly affecting hairy areas often showing characteristic greasy yellowish scales These patterns may merge together A red scaly or exudative eruption of the scalp, ears, face and eyebrows. May be associated with chronic blepharitis and otitis externa . 2. Dry scaly ‘ petaloid ’ lesions of the presternal and interscapular areas. There may also be extensive follicular papules or pustules on the trunk ( seborrhoeic folliculitis or pityrosporum folliculitis ). 3. Intertriginous lesions of the armpits, umbilicus or groins, or under spectacles or hearing aids.

40. Cause not obviously related to seborrhoea . It may run in some families often affecting those with a tendency to dandruff overgrowth of the pityrosporum yeast skin commensals plays an important part in the development of seborrhoeic eczema. This fits well with the fact that seborrhoeic eczema is often an early sign of AIDS, and that it responds to anti-yeast agents such as topical ketoconazole shampoo or cream. Seborrhoeic eczema may affect infants but is most common in adult males. In infants it clears quickly but in adults its course is unpredictable and may be chronic or recurrent

41. Areas most often affected by seborrhoeic eczema Areas most often affected by seborrhoeic eczema

42. Complications Furunculosis In the intertriginous type, superadded Candida infection is common . Investigations None are usually needed, but bear possible HIV infection and Parkinson’s disease in mind.

43. Treatment Therapy is suppressive rather than curative and patients should be told this Topical imidazoles are perhaps the first line of treatment. 2 % sulphur and 2% salicylic acid in aqueous cream , It may be used on the scalp overnight Shampoo contain ketoconazole , tar, salicylic acid, sulphur , zinc or selenium sulphide For intertriginous lesions, a weak steroid – antiseptic or steroid – antifungal combination is often effective. For severe and unresponsive cases a short course of oral itraconazole may be helpful .

44. Discoid (nummular) eczema Cause No cause has been established but chronic stress is often present. A reaction to bacterial antigens has been suspected as the lesions often yield staphylococci on culture, and as steroid–antiseptic or steroid–antibiotic mixtures do better than either separately. Presentation and course common pattern of endogenous eczema classically affects the limbs of middle-aged males The lesions are multiple, coin-shaped, vesicular or crusted, highly itchy plaques, usually less than 5 cm across. The condition tends to persist for many months, and recurrences often appear at the site of previous plaques. Treatment With topical steroid–antiseptic or steroid–antibiotic combinations

45. Pompholyx Cause cause is usually unknown, but is sometimes provoked by heat or emotional upsets or small amounts of nickel in food, in subjects allergic to nickel The vesicles are not plugged sweat ducts. Presentation and course It is tiresome and sometimes very unpleasant form of eczema recurrent bouts of vesicles or larger blisters appear on the palms, fingers and/or the soles of adults. Bouts lasting a few weeks recur at irregular intervals. Secondary infection and lymphangitis are a recurrent problem

46. Investigations Sometimes a pompholyx like eruption of the hands can follow acute tinea pedis (an ‘ ide reaction’). Swabs from infected vesicles should be cultured for bacterial pathogens. Treatment Aluminium acetate or potassium permanganate soaks, followed by applications of a very potent corticosteroid cream, are often helpful. Appropriate antibiotics should be given for bacterial infections.  

47. Gravitational (stasis) eczema Cause Poor circulation, often accompanied by obvious venous insufficiency. Presentation and course A chronic patchy eczematous condition of the lower legs, sometimes accompanied by varicose veins, oedema and haemosiderin deposition When severe it may spread to the other leg or even become generalized. Complications Sensitization to local antibiotic applications or to the preservatives in medicated bandages. Ulcer

48. Gravitational (stasis) eczema Treatment elimination of oedema by elevation, pressure bandages or diuretics. A moderately potent topical steroid may be helpful, but stronger ones are best avoided. Bland applications (e.g. Lassar’s paste or zinc cream BNF, or medicated bandages) It is liable to persist, despite surgery to the underlying veins.

49. Asteatotic eczema Cause Occur in old age patients always have had a dry skin and a tendency to chap. the removal of surface lipids by over-washing, the low humidity of winter and central heating, the use of diuretics and hypothyroidism play a rule. Presentation and course common and itchy pattern of eczema occurs usually on the legs of elderly patients. Against a background of dry skin, a network of fine red superficial fissures creates a ‘crazy paving’ appearance Very extensive cases may be part of malabsorption syndromes, zinc deficiency or internal malignancy. Treatment A mild or moderately potent topical steroid in a greasy base, and aqueous cream as a soap substitute for the area. Baths should be restricted until clearance. Thereafter, daily use of unmedicated emollients usually prevents recurrence.

50. Localized neurodermatitis (lichen simplex) Cause The skin is damaged as a result of repeated rubbing or scratching, as a habit or in response to stress, but there is no underlying skin disorder. Presentation and course A single, fixed, itchy, lichenified plaque Favourite areas are the nape of the neck in women, the legs in men and the anogenital area in both sexes. Lesions may resolve with treatment but tend to recur either in the same place or elsewhere. Treatment Potent topical steroids or occlusive bandaging, where feasible, help to break the scratch–itch cycle. Tranquillizers are often disappointing.

51. Juvenile plantar dermatosis Cause This condition is thought to be related to the impermeability of modern socks and shoe linings with subsequent sweat gland blockage, and so has been called the ‘toxic sock syndrome’! Some feel the condition is a manifestation of atopy . Presentation and course The skin of the weight-bearing areas of the feet, particularly the forefeet and undersides of the toes, becomes dry and shiny with deep painful fissures that make walking difficult. The toe webs are spared. Onset can be at any time after shoes are first worn, and even if untreated the condition clears in the early teens .   Treatment wear cotton or wool socks. An emollient such as emulsifying ointment or 1% ichthammol paste, or an emollient containing lactic acid, is as good as a topical steroid.

52. Napkin (diaper) dermatitis Cause The most common type of napkin eruption is irritant in origin, and is aggravated by the use of waterproof plastic pants and the overgrowth of yeasts.   The mixture of faecal enzymes and ammonia produced by urea-splitting bacteria, if allowed to remain in prolonged contact with the skin, leads to a severe reaction. Presentation The moist, often glazed and sore erythema affects the napkin area generally with the exception of the skin folds, which tend to be spared. Complications Superinfection with Candida albicans is common, and this may lead to small erythematous papulesor vesicopustules appearing around the periphery of the main eruption. Differential diagnosis infantile seborrhoeic eczema candidiasis .

53. Treatment It is never easy to keep this area clean and dry, but this is the basis of all treatment. superabsorbent diaper is best and should be changed regularly, especially in the middle of the night. The area should be cleaned at each nappy change with aqueous cream and water. Protective ointments (e.g. zinc and castor oil ointment) or silicone protective ointments are often useful As are topical imidazole preparations that stop yeast growth Potent steroids should be avoided but combinations of hydrocortisone with antifungals or antiseptics are often useful

54. The END