1. Contact irritants: Intolerance to wool, water, solvents, and
disinfectants is common. This can cause major problems for adults
working in jobs that require exposure of the hands to irritating
chemicals. The role of contact allergens is unclear. There is little
data to support routine allergy testing, dietary, or environmental
manipulation in these individuals. A few atopics have true delayed
hypersensitivity reactions to: nickel, cobalt, balsam of Peru,
fragrance, lanolin, neomycin, and topical steroids. A potentially
serious problem is a Type 1 reaction to latex.
2. Aeroallergens (house dust mite, pollen, molds, human and
animal dander): Some AD improves in a dust-free environment and with
avoidance of seasonal allergens such as pollens and molds.
3. Microbial organisms: Staphlococcus aureus is the main culprit
seen in atopics, and it may be present in increased amounts in the
normal-looking skin of atopics. Improvement is frequently noted when
these patients are treated with appropriate antibiotics.
4. Hormones: Some patients experience exacerbations of their
disease with pregnancy, menses, menarche, and/or menopause.
5. Stress: This is a definite factor in exacerbations of AD.
Maladaptive family behaviours may contribute to the longevity of the
disease. Depression and anxiety can be a result or potentiator of
AD. When AD patients experience stress, their overall tolerance for the
disease is decreased and this can lead to depression as well as a
worsening of pruritus.
6. Climate: Changes in AD are seen when temperature changes are
maximal, i.e., from hot to cold or vice versa. For this reason, AD is
often exacerbated in the spring and fall when weather changes are
greatest. Even the sudden cooling that occurs when a person changes
into pyjamas at night can trigger an intense itch in an atopic.
7. House dust mites: The major allergen in house dust is found in
mite feces. Mites live on human skin scales and are more numerous in
the atopic scale found in bedding, furniture, and carpets than in
non-atopic scale--atopic scales are apparently more nutritious to the
mite. Exacerbations of AD are presumed to be due to both inhalation and
skin exposure to this allergen.
8. Diet: This whole area is very controversial,
but the following conclusions are important:
- Breastfeeding appears to decrease the prevalence of AD in high
risk children for a few years. In one study, mothers avoided cow's milk,
egg, and peanut during the last trimester of their pregnancies and
during lactation. They avoided feeding cow's milk to their babies until
the infants were a year old, egg for 2 years, and peanut and fish for 3
years. There was a significant reduction in food allergy before 2 years
of age, but by age 7 there was no difference with respect to food or
aeroallergen allergy, AD, or asthma.
- Food allergy/intolerance may trigger AD in a small number of
patients (mainly children). Often it will present with erythema around
the mouth and face that occurs with the contact of certain foods,
especially tomatoes.
- When conventional treatment of AD in children fails, food
allergy/intolerance should be considered.
- In children, sensitivity to food (with the exception of peanut)
tends to disappear after the age of 1 year. After this age, eliminated
foods can be gradually re-introduced.
- To date there is no study to suggest that AD patients have a
higher risk of anaphylaxis.
- The presence of food allergy indicates a prognosis of
severe AD and of associated respiratory atopy. Unfortunately,
the public appears to believe that all AD is secondary to food allergy.
Oh, that it were that simple!!
STOP!Review
Questions
- What bacterial organism is commonly found in AD?
- What role does climate play in the course of AD?
- What is the connection between food allergy and AD?
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