Treatment for Atopic Dermatitis (AD or eczema) is multidimensional, involving
four main aims. These are improving the skin barrier function, reducing
or containing the inflammation, identifying the responsible triggers and
preventing any secondary infection.
The skin barrier function is impaired, firstly, due to reduction in skin
lipids, causing moisture loss, and secondly due to mutation of the skin
barrier gene filaggrin. Emollients have been a standard medication in
atopic dermatitis and when used with steroids they have an anti-inflammatory
effect.
Topical therapy
There are a number of treatment options that can be applied to affected
areas of skin topically.
Topical corticosteroids
Corticosteroids have been, largely, the first choice of medication in
atopic dermatitis for the last 50 years. They come in 7 levels of potency.
The more potent ones produce more adverse side effects. So do longer duration
therapies. Amount of absorption of corticosteroids depends on the skin
thickness. Generally, the less potent corticosteroids are used on areas
with thinner skins, such as, eyes, genitalia and face. Palms and soles
may need more potent corticosteroids since the skin at these places is
thicker.
In children, who have a low body volume to skin surface area ratio, the
chances of more corticosteroid absorption is higher. Therefore potent
corticosteroids are avoided in children, because of side effects. Low
potency corticosteroids are generally used at the beginning of treatment
and for maintenance therapy, whereas, higher potency corticosteroids are
used when there are flares.
The advantages of corticosteroids are many. They are cheaper than most
other drugs, are available in a variety of preparations and have proven
clinical effectiveness. They are available as creams, lotions, ointments,
solutions gels and foams.
However, the use of corticosteroids is limited by some very adverse
effects they produce. The local side effects can include, skin atrophy,
acne, glaucoma and cataracts. The systemic side effects include growth
suppression and osteoporosis.
Calcineurin inhibitors
These drugs have been recently introduced for treating eczema and have
been approved for treating children over 2 years of age. They have anti-inflammatory
effects and do not contain any steroids. They can be used along with topical
corticosteroids. These medications have been found to be as or more efficacious
than some of the higher potency corticosteroids. Calcineurin inhibitors
do not have the more serious side effects of corticosteroids and can therefore
be used in places where the skin is thinner. The most common side effect
is burning at the application site. Other side effects include photosensitivity,
erythema and itching.
Coal tar
Coal tar and its derivatives have been used to treat atopic dermatitis
for decades and are as effective as the highest potency steroids. They
have anti-itching and anti-inflammatory effects and are recommended for
use in chronic cases of atopic dermatitis. Coal tar can be used singly
or in combination with topical steroids. Side effects of coal tar are
photosensitivity and folliculitis, but the major drawbacks are its odor
and dark color which stains clothes.
Systemic therapy
The medications in the systemic therapy of atopic dermatitis include
oral antihistamines, oral steroids, systemic immunomodulators, phototherapy
and antimicrobials.
Antihistamines and steroids
Sedating and non-sedating oral antihistamines are not good at relieving
itching in most cases, but they may provide some relief to patients having
sleep disorders (secondary to itching or allergic rhinitis), urticaria
or allergic rhinitis. Systemic steroids are normally used to treat the
more severe cases and that too for short durations. Use of systemic steroids
raises concerns about side effects, the more serious one being recurrence
of the condition after discontinuation of their use.
Immunomodulators
In more refractory cases of eczema, immunomodulators are used, but constant
monitoring is required to detect any side effects. Long term use of immunomodulators
is not advised but patients may have a relapse if the medication is discontinued.
Some immuno-modulators work quickly in two weeks, in the more severe cases,
but produce several side effects. These include renal toxicity, hypertension
and nausea. A slow acting immuno-modulator, known as, Azathioprine, has
been developed but has side effects, such as, bone marrow suppression,
hypersensitivity reactions and pancreatic.
Phototherapy
Ultraviolet light therapy is another method for treating the refractive
cases of eczema. This therapy has an anti-inflammatory effect on the cells
of the immune system. There are various kinds of UV phototherapy for treating
various kinds of atopic dermatitis. Topical steroids may be used with
some types of UV therapy, with option later to reduce steroid dosage.
Side effects include singing, burning, premature ageing of skin and pigmentation.
Antimicrobials
Antibiotics are preferred, especially, when there is a heavy infection
of staphylococcus bacteria associated with the eczema. Currently, systemic
antibiotics are preferred because of increasing cases of resistant staphylococcus.
Topical steroids and calcineurin inhibitors can also reduce staphylococcus
count. Antiviral treatment is critical in cases with eczema herpeticum,
as it can become life threatening.
