HISTORY
A 6-year-old girl is brought to dermatology for evaluation of several problems: “dry skin” present since birth, as well as new “bumps” that her family has noted recently. There are additional questions about her skin, mostly revolving around its sensitivity (illustrated by overreaction to mosquito bites) and whether there is a connection to food allergy.
She has seen an allergist, who ordered testing that revealed a sensitivity to airborne allergens (eg, dust, pollen, mold). However, the allergist assured the patient and her family that none of these had any relation to her skin complaints.
The child’s two older siblings have similar dermatologic problems, and one also has asthma. All three had terrible diaper rashes as infants.
The parents, who were both allergy-prone as children, wonder if there is a connection between their children’s skin problems and stress. They have noticed a worsening of the itching and scratching with increased levels of anxiety or tension.
EXAMINATION
The child has extremely dry skin all over her body, but especially on her extremities. Her palms exhibit an excessive number of lines. The “bumps” on her skin are widely scattered and firm and average 1 to 1.5 mm in diameter. Several have umbilicated centers.
Her periorbital skin is dark, slightly scaly, and edematous, especially beneath the eyes, where extra lines have been created by the edema.
A faint but definite transverse white line is evident on her nose. Transverse ridging is seen on several fingernails.
DISCUSSION
This child and her family could serve as walking textbooks on an extremely common diagnosis: atopic dermatitis (AD), which involves a constellation of skin issues combined with an allergic constitution.
Major diagnostic criteria include a low threshold for pruritus, a personal and/or family history of eczema and atopy, and chronic or chronically relapsing eczematous dermatitis occurring in characteristic distributive patterns (the face and extensor surfaces on children; flexural surfaces on older children and adults).
Minor diagnostic criteria number at least 23, and include several of our patient’s signs: Dennie-Morgan folds, dry skin (xerosis), onset of problems early in life, susceptibility to skin infections such as molluscum, periorbital darkening (so-called allergic shiners), hyperlinearity of the palms, and the transverse nasal crease between the upper two-thirds and lower one-third of her nose, created by years of habitual upward rubbing. The observation by her parents that stress exacerbates the problem is yet another corroborative finding.
It’s important to note that in families like this one, not every child experiences the full measure of allergic and cutaneous problems. It’s not at all unusual, for example, to see one child with dry, sensitive skin and no obvious allergic phenomena, while a sibling might have minimal skin issues but major problems with asthma and seasonal allergies. It’s no wonder families are often quite confused, particularly when they are being told contradictory things by well-meaning medical providers and family members.
It’s critical for us, as medical providers, to have an accurate overview of how utterly common atopic dermatitis is, along with its myriad manifestations. This problem already affects at least 15% of the population to one degree or another, and its incidence is growing rapidly worldwide, primarily among the relatively affluent.
Much research has been done regarding the genetic and physiologic bases of AD, but those issues remain far from settled. What we do know is that AD patients have two basic problems: First, their skin is too thin and dry to serve as an effective barrier. Second, they have a dysfunctional and overreactive immune response to a multitude of allergens that present minor issues to the rest of us. One theory holds that the thin skin is what allows antigens to penetrate and set off the dysfunctional immune response.
In any case, it’s important to be able to recognize this common condition, and to be able to educate patients and parents. The inherited nature of the problem must be stressed, as the manifestations will likely continue (in one form or another) despite any treatment that is attempted. These are key pieces of information, without which patients and parents worry needlessly about the wrong things (often, food is blamed, though it is almost never the cause), to the neglect of potentially effective measures that could be taken.
TAKE-HOME LEARNING POINTS
• Dennie-Morgan folds represent one of many minor diagnostic criteria for atopic dermatitis (AD).
• It is difficult to overstate the pervasive nature of AD, both because it affects so many people (at least 15% of the population) and because it has a variety of manifestations (eg, dry and/or sensitive skin, eczema, hives, asthma).