1. Dermatitis and its variants
Dr Daniel Hewitt
Dermatologist
Skin and Cancer Foundation Westmead
2. Objectives
To understand the basic pathology of
dermatitis
To understand its main causes and
precipitants
To appreciate the different possible
presentations and the effect on the patient
To list therapeutic options
To appreciate some of the variants of
dermatitis
3. Introduction
Dermatitis is extremely common in General Practice and Dermatology.
There are many forms, of which atopic dermatitis is the most common.
Patients and their families are greatly disturbed by the itch of
dermatitis.
Eczema and dermatitis are synonymous.
Literally, dermatitis is “inflammation of the skin.”
More specifically it is defined by a presentation of itchy, scaly and
usually erythematous skin. Histologically, the hallmark is spongiosis
or oedema in the epidermis – the keratinocytes in the epidermis are
pushed apart by this fluid.
5. Atopic dermatitis
Atopic dermatitis affects approximately 15% of children and this prevalence is
increasing in Western societies.
It presents in the first year of life in 60%
The causes are complex and multifactorial.
There is a genetic susceptibility – this predisposes to a defect of the epidermal
barrier function. Patients lose the moisture in the skin more readily due to
differences in proteins (especially filaggrin) in the epidermis.
Subsequent immune stimulation and immune regulation lead to chronic
inflammation and the itch and erythema of dermatitis.
Patients may also have a tendency to form IgE antibodies and develop asthma
and/or hayfever. However, atopic dermatitis is not primarily an allergic
disease.
6. Clinical features
Atopic dermatitis is a clinical diagnosis
Itching is usually the most troublesome symptom and may wake the
patient at night.
There is poorly defined erythema often with a dry, scaly skin. This is
usually on the face in babies and spreads to the flexural surfaces
most characteristically in older children.
There may be weeping or crusting superimposed. Crusting may
represent superimposed bacterial infection (impetiginisation.)
Lichenification or thickening of the skin with accentuated skin lines can
occur in more chronic cases.
Excoriations (scratching induced areas of skin loss) are common.
14. Triggers
Atopic dermatitis is essentially endogenous,
but a number of triggers can flare the disease.
These generally dry or irritate the skin
– Soap, shampoo, bubble bath
– Water itself, especially prolonged or frequent contact
– Wool
– Heat
– Grass, sand
– Citrus fruits
– Stress
Allergies are possible but less common than irritants.
15. Management
This comprises two main aspects
1 Controlling the inflammation
2 Restoring the barrier with regular moisturisation
The management plan must be well understood by patients or their
carers. The treating doctor must give detailed but clear
explanations and ensure the plan is agreed to by the carers.
Atopic dermatitis is a chronic disease with no cure. It can be controlled
but a long-term management plan must be established.
The psychosocial aspects of both the disease and the need for ongoing
management are often profound.
16. Topical corticosteroids are essential in the management of acute dermatitis. Parents are
often very concerned about possible side effects but when used appropriately they
are very safe and effective.
A topical steroid that is potent enough and appropriate for the site is to be used in the
short term to settle the dermatitis.
Face, nappy area, closed flexures (mild potency)
– 1% hydrocortisone ointment
– Desonide .05% lotion
– More severe, betamethasone 0.02% ointment
Widespread low grade disease (moderate potency)
– Betamethasone 0.02% ointment
– Triamcinolone 0.02% ointment
More severe disease (more potent)
– Methylprednisolone 0.1% ointment
– Mometasone ointment
Lichenified areas (more potent)
– Mometasone ointment
– Methylprednisolone fatty ointment
– Betamethasone 0.05% diproprionate
17. Moisturisation is essential. There are many products and methods, but
the regime must be acceptable to the patient.
Bath oils and moisturising creams are most commonly used. More
greasy preparations (eg “dermeze”) are generally better
moisturisers but also less pleasant for patients to use.
A typical regime would be
QV bath oil in the bath
QV soap free wash to wash skin – no soap or bubble bath to be
used
Gently pat dry after bath
Apply QV cream all over in first few minutes after dried
Moisturiser may need to be applied multiple times a day if the skin is
very dry.
18. Irritant contact dermatitis
This is inflammation of the skin due to the effect of a drying or irritating
influence on the skin. This effect accumulates over time and
dermatitis results when the natural healing mechanisms of the skin
are overcome by the repeated damage.
It is most often seen in people who frequently wash their hands, such
as housewives, hairdressers, mechanics.
Those with atopic dermatitis are prone
to this as adults.
21. Allergic contact dermatitis
This is due to a specific allergen that has contacted the skin and
triggered a type IV delayed type hypersensitivity reaction.
In can co-exist with both atopic dermatitis and irritant contact
dermatitis.
Some occupations, such as hairdressers, plumbers, carpenters and
construction workers are particularly prone as they are exposed to
both irritants and allergens.
Patch tests are done to assess for allergic contact dermatitis. Panels of
allergens are applied to the back and the patient is assessed for
evidence of an allergic reaction
28. Discoid dermatitis
This is a clinical form of dermatitis in which there are well defined
lesions.
It can present in atopic dermatitis and often occurs in those with a
generally dry skin.
It can be quite resistent to treatment and often leaves some residual
colour change in the skin (post-inflammatory hyperpigmentation.)
31. Asteatotic dermatitis
Patients with very dry skin can develop this form of characteristic
dermatitis. It has a “crazy-paving” appearance, due to cracks
developing in the epidermis.
It is particularly common in the elderly and is often seen in air-
conditioned environments, such as hospitals, where the air is dry.
34. Venous stasis dermatitis
This is common in those with venous insufficiency. When the valves in
the lower legs become faulty from previous thrombosis or chronic
pressure on the venous system, excess fluid accumulates in the
legs.
The skin tissues become inflamed and itchy.
There may also be scaling, weeping and ulceration.
38. Seborrheic dermatitis
This is a form that presents with ill-defined pink patches often with
yellow or greasy scale.
It is most common over the medial cheeks, eyebrows and forehead and
can be associated with dandruff. It also occurs over the chest and in
the groins and axillae.
It has different causes and treatments to atopic dermatitis. There is a
relation to the Malassezia yeast and it frequently flares with physical
or psychological stresses.
Treatment inculdes antifungal, anti-inflammatory and keratolytic
preparations.
41. Conclusion
Dermatitis is the most common cause for an itchy skin
eruption.
Usually topical treatment is adequate, but sometimes
patients require ultraviolet therapy or systemic therapy.
There are many different causes and variants of dermatitis
and these all have characteristic features.
