By Gary M. White, MD
A diffuse red, scaly, eczematous eruption in a child with accentuation in the folds.
Atopic dermatitis (AD) is a common eczematous rash affecting children with an inherited tendency toward dry skin, allergies, asthma and hay fever. It is caused by both a defective skin barrier function and allergy to a wide variety of environmental and dietary allergens. IgE levels tend to be high. An atopic dermatitis handout for patients is available.
Filaggrin (FLG) helps aggregate keratin filaments in the upper epidermis as well as helps the skin retain moisture. About 10% of the population has loss of function mutations in the FLG gene and therefore are genetically predisposed to dry skin. Patients with mutations in the FLG gene are more likely to develop:
Of note, the development of AD during late childhood or adulthood is not associated with FLG mutations [British Journal of Dermatology 2015, 172: 455–461]. Furthermore, African-Americans are very unlikely to have FLG mutations.
Evidence is mounting that high levels of Staph aureus on the skin drive AD.
The contribution by biofilms is also actively being studied.
Some divide AD into external and internal. The clinical appearance is the same, but extrinsic AD is characterized by high serum IgE, as well as a personal and familial history of atopy and specific IgEs to food or aeroallergens. Intrinsic AD patients have normal serum IgE, absence of other atopic diseases, and lack of allergen-specific IgEs. External AD represents approximately 80% of adult atopic patients and intrinsic about 20%. Intrinsic AD has a lower frequency of FLG mutations.
Atopic dermatitis is an eczematous condition. In infants, almost any site may be affected, although the cheeks commonly develop a red, scaly, or glazed look. Often, the saliva from drooling during sleep or friction aggravate the condition in this area. As the patient gets older, the eczema often becomes more flexural in location. Still, any part of the body may be affected, especially if scratching occurs. Itching may be intense and the patient may scratch incessantly. Atopic skin is often colonized with staphylococcus aureus and secondary infection may occur. Superinfection by herpes simplex may also occur (see eczema herpeticum).
Common triggers that may flare the eczema include airborne allergens, infection (e.g., a URI), dry, cold air, and secondary skin infection (e.g., by staphylococcus). Less commonly, food allergies (especially eggs, peanuts, milk, fish, soy and wheat) and allergic contact dermatitis may flare eczema. Sweating can induce significant pruritus [Br J Dermatol 2009; 160:642–4].
Diagnostic criteria are usually based upon four key items [BJD 1994;131;383]:
See here for a discussion.
Rapid control of even recalcitrant AD may be achieved in the vast majority of patients with once or twice a day baths followed by the application of a topical steroid (TS) ointment [Dermatitis. 2014 Mar-Apr; 25(2): 56–59]. Prehydration is critical to remove previous oils, vehicles, crust, bacteria, etc., as well as to greatly increase the penetration of the topical steroid. Note, this is very similar to the Soak and Smear technique. There is conflicting data, however, as a 2-week comparison study of a topical steroid (either triamcinolone or hydrocortisone) applied to hydrated skin vs dry skin showed no difference in improvement of atopic dermatitis [JAAD 2016;75;306].
An atopic dermatitis handout is available. Steroid phobia is rampant and usually needs to be addressed. Tell parents that use of stronger steroids for <= 2 weeks is safe and needed.
Maintenance therapy may consist of:
In general, the thicker the better for atopic dermatitis during the clearing phase. However, some patients may not tolerate ointments. Cream may be used instead, or an oil vehicle followed by wet wraps [J Drugs Dermatol 2016;15;114].
Phobia over the use of topical steroids is prevalent--however the risk of atrophy is quite low with proper use. In one study of 70 children with eczema or eczema/psoriasis overlap and a mean age 3.2 years [Ped Derm 2011;28;393], potent (e.g., betamethasone dipropionate ointment), moderate (e.g., betamethasone valerate ointment) and weak (e.g., HC 1% ointment) steroids were all used providing excellent control with no atrophy seen over controls. Their patients used potent topical steroids 2-3/day when flaring, then reduced to moderate strength BID for 3 days, and then low potency and emollients for maintenance. Wet wraps were allowed, but plastic wrap occlusion was not. From that study, the mean number of grams per month of different strengths of TS was:
It is important to prescribe a sufficient quantity of topical steroid. For example, during a two week initial total body treatment, many patients need a 1 lb jar (454 g).
Most children have specific problem areas that constantly flare (e.g., the face). Pimecrolimus or tacrolimus may be very helpful in these areas. Once relatively good control is achieved with a TS, the topical calcineurin inhibitor (TCI) may be applied BID to maintain the clear skin. Note that this use is off-label as TCIs are not recommended for prolonged daily use. Long-term experience, however, has shown this to be a safe approach. Many specialists use TCIs for the eyelids.
Based on the current review of the literature and their clinical experience, a large group of experts in pediatric dermatology concluded that pimecrolimus cream and tacrolimus ointment are safe and effective for the treatment of infants at least 3 months of age with AD [Pimecrolimus in atopic dermatitis: Consensus on safety and the need to allow use in infants. [Pediatr Allergy Immunol. 2015 Jun; 26(4): 306–315].
Crisaborole is a small compound that effectively penetrates the skin to inhibit PDE4. The FDA has approved Eucrisa (Anacor Pharmaceuticals, crisaborole) ointment to treat mild to moderate eczema in patients two-years-of-age and older. It is applied twice daily. Like the TCIs, crisaborole will be used as a steroid sparing agent and for maintaining normal skin. It may have fewer side effects (e.g., burning and itch) than tacrolimus and pimecrolimus.
A systematic review and meta-analysis concluded that there is level-1a support of the preferential use of corticosteroids over TCIs as the therapy of choice for AD because of increased side effects of TCIs (burning and itching), and no increase incidence of atrophy when TSs are used correctly [JAAD 2016;75;410].
One report advocated the use of a compounded steroid, antibacterial and moisturizer. The recipe is as follows: Betamethasone valerate cream 0.1% 30 grams, mupirocin 2% cream 22 grams and vanicream or equivalent base 400 grams mixed to a total mass of 452 grams. Apply 4/day for 7 days, then BID for 5 days, then daily as needed [PD 2017;34;322].
The latest evidence does not show benefit of adding bleach to the water bath. Water bath along followed by moisturization or topical medication improves skin in atopic dermatitis.
Infants living in areas with a high calcium carbonate concentration in the water supply and that have a loss of function FLG mutation are at increased risk for developing AD.
For discussion of therapy for resistant disease, see atopic dermatitis, severe.
Much debate exists over how often to bathe the child with AD. Daily? Twice a week? Various studies have investigated this and there are conflicting opinions. In this author's opinion, the key point that is often left out of the discussion is maximizing the effectiveness of the topical steroid. If the skin is in good shape and only moisturizing is needed, then applying Vaseline 1-4 times a day and bathing only twice a week is fine. However, if the eczema is active and the use of a topical steroid is needed, then cleansing the skin daily and applying the topical steroid within minutes of exiting the bath/shower is highly effective.
In a study of the calcineurin inhibitors for long-term treatment of atopic blepharoconjunctivitis, both tacrolimus and pimecrolimus were safe and effective. Tacrolimus ointment was preferred as it was slightly more effective [Jama derm May 2014;150:571].
Scratching should be discouraged. Sedating antihistamines (e.g., diphenhydramine, hydroxyzine) are helpful for the child who scratches at night. They do not make eczema better. They merely make the patient more drowsy so s/he is less likely to scratch. See antihistamines for dosing of children's Benadryl and age restrictions. Topical antihistamines don't help.
Sleeping is often significantly disrupted in AD. In one placebo-controlled study of melatonin, 3 mg QHS, vs placebo for 4 weeks in children with AD, melatonin significantly improved sleep and reduce the severity of the AD over placebo [JAMA Pediatr 2015 Nov 16].
In North America and Asia (but not in Europe), AD is associated with being overweight/obese [JAAD 2015;72;606]. This brings up the idea of weight loss as a therapeutic intervention for AD (as is true for psoriasis).
If after doing well for a while, the parents call saying the child is flaring, the patient generally should be seen to rule out secondary infection by staphylococcus or herpes. If the child gets repeated staph infections, consider bleach baths (see above) for the child, Hibiclens in the shower for family members and bacitracin up the nose for all.
Parents often want to know the likelihood of their child growing out of AD. In one study, of those children who had AD at 1 year of age, almost 50% no longer had AD by 4 years of age.
Scratching at night may be an important contributor to treatment resistance. In one study [BJD1999;141;82], patients with severe AD spent about 15% of their sleeping time scratching. Patients with moderate AD spent an average of 5-6% of their sleeping time scratching. Clearly, any methods that decrease nocturnal scratching will improve the skin lesions.
Glazed cheeks and a flexural rash.
Atopic dermatitis of the eyelids in a child and Dennie-Morgan folds.
Hertoghe Sign. Loss of the lateral eyebrow from rubbing.
The neck is commonly involved.
Scratching commonly results in linear lichenification.
Crusting or pus usually means secondary infection. Culture of the knees showed Staph. Culture of the corner of the mouth grew herpes simplex.
Herpes Simplex (duration 1 week so pustular) in a child with eczema (two prurigo nodules above pustules)
All other spots of this girl's atopic dermatitis were getting better except this one on the ankle. Koh positive for fungus.