Atopic Dermatitis

Atopic dermatitis translates into “inflamed skin in individuals with a tendency towards allergic reactions”.

Atopic individuals are hypersensitive to environmental allergens (pollen, dust, animal dander), food ingredients, clothing, chemicals, climate changes, and emotional stress. They are prone to developing eczema (which just means irritated skin), along withallergies and asthma. Although individuals are not required to have all three entities to receive the diagnosis, approximately 30% develop asthma and 35% develop allergies (such as hay fever).

Involvement of the elbow crease. From Fitpatrick’s Color Atlas & Synopsis of Clinical Dermatology.

What does atopic dermatitis look like, and how does it feel?

1. Across all ages and time course of disease (e.g. acute vs. chronic), the skin is DRY! The skin can be so dry that it cracks and forms fissures.
2. It is ITCHY! Its itchy nature initiates a vicious cycle: as kids scratch, an even itchier rash appears.
3. In its acute stage (when it is relatively new), atopic dermatitis appears as red, puffy skin. Small blisters can form, and these blisters often ooze. This type of skin is referred to as “weepy”. These lesions can also scale and crust.
4. In its chronic stage (when the rash has been around for some time), atopic dermatitis appears lichenified. This is a fancy word which just means that the skin is thick due to repeated itching or rubbing.

Atopic dermatitis in an infant. From eMedicine: http://emedicine.medscape.com/article/1049085-media

The location/distribution of the rash is very important, and this can vary by age:

• In INFANCY (0-2 years old), the rash is on the face (forehead, cheeks, chin, behind the ears), on the scalp, on the trunk, on the elbows, and on the knees. It usually spares the nose and diaper area. Since the rash is new, thickened skin secondary to itching and rubbing is not seen.
• In CHILDHOOD (2 years old-puberty), the rash is in the bend of the elbow, behind the knees, on the wrists and ankles, and on the neck (it can be useful to think of places where the skin creases). Lichenification is more common, and you may also see scratched skin and crusting.
• In ADULTHOOD (after puberty), the distribution is similar to the childhood form. You may also see involvement of the upper arms, back, fingers, feet, and toes.

The cause of atopic dermatitis is unknown.

It is common for these individuals to have atopic family members (relatives with atopic dermatitis, allergies, or asthma), so it may be partly genetic. The environment has been shown to play a role, and there are some theories that the skin of atopic patients is structured to allow increased entrance of outside pathogens into the body, inducing an allergic reaction.

Atopic dermatitis begins to appear around 2 months of age. By one year, 60% of the patients who will develop atopic dermatitis have already manifested signs and symptoms. By five years, 90% of patients have done so. Only 10% of individuals develop atopic dermatitis between the ages of 6 and 20. As these numbers imply, atopic dermatitis usually occurs in childhood. In fact, 10-12% of children are believed to have this condition (as compared to 0.9% of adults).

What happens to these children as they grow up?

40% of children will continue to have atopic dermatitis into adulthood. 60% of children will be free of symptoms in early adolescence. However, it is not always these same individuals who remain symptom-free into adulthood: up to 50% may have recurrences later in life!

Some good things to know:

• Atopic dermatitis is usually worse in the winter and better in the summer.
• Pustules could indicate an acute bacterial infection in skin affected by atopic dermatitis.
• Emotional stress can lead to flares.
• Frequent bathing and hand-washing can make atopic dermatitis worse.
• Atopic dermatitis CAN be managed!

If you would like to learn more about atopic dermatitis, the National Institute of Arthritis and Musculoskeletal and Skin Diseases has posted a comprehensive handout on their website.

REFERENCES:
Krafchik BR. Atopic Dermatitis [Internet]. eMedicine. http://emedicine.medscape.com/article/1049085-overview. Accessed on October 4th, 2009.

Marks JG, Miller JJ. Eczematous Rashes. In: Lookingbill & Marks’ Principles of Dermatology. 4th ed. Elsevier Inc; 2006:108-111.

Wasserbauer N, Ballow M. Atopic dermatitis. Am J Med. 2009;122(2):121-125.

Williams HC. NEJM. 2005;352(22):2314-2324.

Wolff K, Johnson RA. Eczema and Dermatitis. In: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 6th ed. McGraw-Hill;2009:34-41.