Eric W. Baum, M.D., M.Sc. Clinical Professor, Department of Dermatology UAB Medical Center
Atopic dermatitis is a chronic inflammatory skin disease with a
multi-varied etiology. It is characterized by pruritus, which can be
quite severe and unrelenting. The skin lesions are polymorphic in
nature and may present as erythema, excoriation, papules, papulovesicles,
lichenified and have a serous exudate.
It is a high prevalence disease that can affect 18 million children
and adults. Psoriasis, another chronic inflammatory disease only
affects 7.5 million people in the United States. Atopic dermatitis
(AD) has a tremendous economic impact on our society. It is
estimated to cost $3.8 billion each year. Co-morbidities include,
social, psychological and quality of life issues. The greatest risk
factor is a family history of atopy.
The diagnosis is usually fairly simple, with rashes on the antecubital fossa and popliteal
areas behind the knees. Minor criteria such as an infraorbital pleat (Dennie Morgan Line)
and discoloration under the eyes (atopic shiners) as well as “chicken skin” on arms, thighs
and cheeks (keratosis pilaris) make this a fairly simple clinical diagnosis. More
sophisticated criteria such as Hanifin-Rajka, The American Academy of Dermatology and
the United Kingdom working party exist for study participants.
Treatment of the disease offers many choices based on symptoms and severity. Various
trigger factors have been elucidated, but even if recognized do not guarantee successful
results. Trigger factors can be classified by 3 general categories.
Topical treatments have been the mainstay of treatment for mild to moderate AD. This
can reduce inflammation, pruritus and infection, but often times, are not able
to adequately control disease symptoms. These include, various potencies of topical
corticosteroids (TCS) based on patients age, body mass and location. Moisturizers are a
mainstay of therapy whether they are humectants, emollients or occlusive with various
excipients to help restore impaired epidermal barrier function.
Oral antibiotics have been replaced by bleach baths, except when skin infection is severe.
Antihistamines only offer sedation to alleviate pruritus to some extent, but do not offer
any help in improving the skin disease. Topical calcineurin inhibitors were approved 15
years ago and do offer improvement in selective patients and for chronic management
due to being non-steroids. They are generally expensive and come with a black box
warning.
A new understanding of molecular level disease mechanisms has begun to offer new
treatments, both topically and systemically. This is beginning to meet the current unmet
need of safe and effective choices for this chronic skin disease.
The first is Eucrisa, a PDE4 blocker approved for topical therapy in mild to moderate
atopic dermatitis. This works by regulating the degradation of cyclic amp which decreases
the production of inflammatory cytokines. Other than itching, it is a well-tolerated topical
alternative and can be used in conjunction with (TCS) to limit their use.
The use of immunosuppressants such as cyclosporine, imuran and methotrexate is
beyond the scope of this article. Systemic side effects limit their use to experienced
clinicians.
The really impactful news was the approval of the first biologic for moderate to severe
AD for patients (adult) 18 years or older. It is an immunomodulator and unlike the
biologics, approved for psoriasis, is not an immunosuppressant. No blood work or TB
testing is required. It blocks (2) of the proven cytokines implicated in the disease of AD,
IL 4 and IL 13. It is called Dupixent (dupilumab). Currently, studies are almost complete
for the indication in adolescents. Phase III studies demonstrated excellent results in
decreasing and clearing the skin signs of this chronic inflammatory disease.
After not having new treatment choices for AD for many years, there are new exciting
treatments now available. The future is even brighter, since many other companies are
now investigating other new products in phase II and III studies.
1. Fonacier Luz MD Peer CME, email. (peercme.com)