Are you worried about itchy skin allergies that keep coming back out of
the blue? You are probably suffering from a skin condition called atopic
dermatitis (AD) better known as eczema. This common and chronic inflammatory
skin disease is also associated with other atopic diseases like asthma
and allergic rhinitis.
Atopic dermatitis has seen a sharp rise with the spread of industrialization
and its associated lifestyle. What’s more, it affects more women
than men and around 65% of patients first develop atopic dermatitis during
childhood. Moreover, unlike other childhood diseases that improve with
puberty, 40% of atopic dermatitis cases either relapse or recur after
reaching adulthood. Its primary causes are generally associated with heredity,
environmental interactions, skin barrier disorders, or immunological reactions.
There are two types of eczema, namely intrinsic (or non-allergic) and
extrinsic (or allergic).
The detection of atopic dermatitis involves tracing its onset in its
three age-related phases of infantile, childhood and adult eczema. Diagnosis
must also take into consideration its other features like heredity, its
chronically relapsing aspect, association with atopic diseases, its characteristic
itchiness, basic biology, etc.
Prevention is always better than cure, so the first step in the management
of atopic dermatitis is reducing the symptoms by identifying the triggers
(allergens) and hence avoiding them. This apart, the therapeutic approach
is aimed at restoring the skin barrier functions with hydration. In eczema,
a skin barrier disorder occurs due to an abnormality in skin lipids, which
in turn results in greater transepidermal water loss. This is caused by
genetic alterations of the epidermal barrier protein filaggrin.
Standard treatments of atopic dermatitis are the use of emollients to
hydrate the skin combined with topical corticosteroids. Wet dressings,
antibiotics for infections and antihistamines are also used. In acute
cases where other treatments fail, systemic therapies are often implemented.
Stress management and patient counseling can also be a vital part of therapy.
Corticosteroids and their usage in atopic dermatitis
Topical corticosteroids are anti-inflammatory drugs with different potencies.
The use of topical corticosteroids combined with moisturizer-based emollients
has been the standard procedure in atopic dermatitis prevention and treatment
for almost 50 years now. This hydrating combination increases the anti-inflammatory
potential of the topical steroids.
The dosage of corticosteroids for eczema
The common recommendation is to start with the use of the least-potent
topical steroid combined with a good skin care routine. Thereafter more
potent topical steroids should be used until the patient gains noticeable
improvement in their skin condition.
The topical steroids should first be used continuously for a few weeks
and then around twice a week. Practitioners generally prescribe its application
twice daily at first and immediately after a bath. This is a dosage recognized
by the European Academy of Dermatology and Venereology. Dosages are then
tapered down to less frequent application to reach the minimum required
to maintain remission of the eczema.
Maintenance doses should be of low-potency. Mid to high potency steroids
should be restricted to the treatment of flares. The associated skin itchiness
(pruritis) is an effective marker in the success of therapy and the dosage
can be decreased (it should be done gradually to avoid flares) until the
discomfort is nil. In children with mild eczema, one can only use brief
and alternating doses of strong steroids. This is as safe and effective
as the sustained use of milder topical steroids.
Contraindications of corticosteroids
It is very important to know how and where to apply a corticosteroid
and this must be an integral part of patient counseling. This is determined
by how much of it is being absorbed into the skin, which in turn is dependent
on the surface area of the skin, the thickness of the epidermis, the preparation
used, drug potency and the use of occlusive dressing.
Here are a few safeguards:
- Avoid Class 1 to 5 topical steroids in body locations with thinner
skin, such as the eyelids, face, mucous membranes, genitalia and intertriginous
areas. These body areas have a greater risk of transepidermal
corticosteroid
absorption.
- It is safe and necessary to use more powerful topical
steroids on the palms and soles, which have a much thicker epidermis.
- Children
are more vulnerable to side effects since they have a low body volume
to skin surface area proportion, which leaves scope for
more absorption of corticosteroids. Hence, strong steroids should be avoided
in kids.
Moreover, the longer the usage and the stronger the topical steroids,
the greater are the risk of side effects. The local side affects of corticosteroids
are:
- Skin striae (lines in the skin)
- Skin atrophy (thinning)
- Telangiectasias (blood vessel formation)
- Perioral dermatitis (eczema
around the mouth)
- Erythema (inflamed skin)
- Acne
- Glaucoma (eye condition)
- Cataracts (eye condition)
Possible systemic side effects are:
- Growth retardation in children
- Repression of the hypothalamic-pituitaryadrenal
axis
- Osteoporosis (bone thinning)
Advantages of corticosteroids
The benefits of using topical steroids are:
- Cost effectiveness
- Large range of usage mediums like creams, lotions,
ointments, solutions, gels and foams
- Established clinical efficacy
How to select a corticosteroid for atopic dermatitis
There are a few rules while making a choice of corticosteroids:
- Ointments are more effective than creams because of better absorption
potential.
- The area of application is also a pointer. For instance,
foams and lotions are easier to apply than ointments on hairy regions.
- Occlusive
dressings are a good option in acute cases as they improve the absorption
and hence enhance therapeutic results. However, since
they also increase chances of side effects they should be restricted
to short
spans of use.
- The selection process should also take into account
the individual needs and preferences of a patient at the backdrop
of drug potency,
preparation,
the body location of the lesions, age, season, environment,
socioeconomic condition, medical history and infections if any.
Corticosteroid combination therapies
One of the latest developments in atopic dermatitis treatment has been
topical calcineurin inhibitors. They are steroid-free anti-inflammatory
medications and can be used along with topical corticosteroids for fewer
side effects from the latter.
What’s more, topical steroids are also often used simultaneously
with psoralen plus UVA (PUVA) therapy that helps reduce dependence on
the former and its side effects.