The Skin is a window on the health of the body and the point of contact
between the body and the outside world. Many illnesses and conditions can
show up in skin changes. Food allergies may show up as skin rashes.
(Dermatitis just means an inflammation of the skin) Interestingly animals
including cats and dogs are very susceptible to skin rashes provoked by
foods.
Urticaria
(hives) The skin is a common target organ
for allergic responses to food. Acute urticaria is characterized by itchy,
transient, red raised lesions, sometimes accompanied by localized swelling (angioedema).
Food allergy accounts for up to 20 percent of cases of acute urticaria
and is a true allergy mediated by antibodies (IgE)
specific to food protein. The skin lesions usually occur within one hour of
eating or contact with the food.
Atopic disease -
which is a condition where an inherited tendency can render a person
susceptible to allergies which may manifest as skin rash on eczema, as a
respiratory problem in asthma and it is thought that migraine may also be
related.
In
infantile eczema the atopic reaction can be provoked by food substances.
The infant gut is easier to penetrate by food molecules
and so the baby is more vulnerable to absorbing antigens. Cows milk protein
is an important factor especially if this is used as a supplement or instead
of breast milk in a susceptible baby. Please note this is the protein which
causes the reaction and this is not related to lactose.
Substitutes such as goats milk or soya can be
used but some children are also allergic to these. Specially prepared milks
in which the proteins are broken down into smaller molecules (eg pregestimil)
can be used in some cases but are very expensive. Breast milk is far the
best. Also allergy-provoking foods such as milk, eggs, fish and peanuts
should be avoided in the breast-feeding mother’s daily diet. Avoidance of
solid foods in babies up to 6 months of age followed by the careful
introduction of the potential allergy-provoking foods such as cow’s milk,
wheat and peanut at 12 months, and eggs and fish only being introduced after
18 months. Up to a third of infantile eczema is food allergy related and
food additives and colourings may also aggravate eczema in older children.
In addition adverse reactions to citrus fruit, tomatoes, pineapples and
Marmite, are common in patients with eczema
Many general or systemic
diseases have also a skin manifestation, For example Coeliac disease
which is basically an intolerance to gluten, has an intestinal set of
symptoms and a generalised symptomatology which can include joint and skin
problems. The skin reaction can be seen as dermatitis herpetiformis which is
a chronic recurring itchy rash.