Dermatite atopique et allergie : quels liens ?

Atopic dermatitis (AD) is a very common chronic inflammatory skin disease in childhood, often the first step in the atopic march. It seems justified to look for a food or a respiratory allergy, being worsening or responsible for the AD. At infant age, some clinical features are consistent with a food allergy: a severe AD, with an early onset, uncontrolled by topical corticosteroids, and a history of immediate-type reactions. As sensitization to food allergens is very common (positive skin prick-test, atopy patch-test or specific IgE), the role of food allergens in worsening AD is difficult to affirm. So, it could be necessary to ask the advice of an allergist, to avoid unnecessary elimination diets. At older age, exposure to aeroallergens cans worsen AD. Looking for an aeroallergen allergy can help to choose the specific immunotherapy, which clinical efficacy on AD seems interesting.     

Different serum interleukin‐12 and sCD30 levels in food‐ and pollen‐sensitized children

It has been proposed that a down-regulation of interleukin (IL)-12 and interferon (IFN)-γ might be related to susceptibility to allergy in early life. The aim of this study was to assess serum IL-12 levels in food-sensitized and pollen-sensitized children and to compare these with another activation marker, sCD30. Twenty children with pollen allergy and 22 food-sensitized children were included. The diagnosis of immunoglobulin (Ig)-E-mediated allergy, suggested by clinical symptoms, was based on skin-prick tests, serum IgE antibodies and total IgE levels. Samples from 24 non-allergic children were used as controls. IL-12 and sCD30 levels were measured by ELISA. It was found that pollen-sensitized patients had normal IL-12 and higher sCD30 levels than controls (114 vs. 63 U/ml, p = 0.028), but, surprisingly, food-sensitized infants showed normal sCD30 and increased serum IL-12 levels (323 vs. 118 pg/ml, p = 0.0001). No differences were found in patients suffering from asthma or allergic dermatitis. Levels of sCD30 and IL-12 determined in May showed a strong correlation with those obtained in November. Interleukin-12 and IgE levels had an inverse correlation (r = –0.494, p = 0.0001) whereas no correlation was found between sCD30 and IgE. Age had a strong negative influence on IL-12 levels in allergic (Z = 4.834, p < 0.0005) and in normal children (Z = 3.00, p < 0.002); by contrast, sCD30 levels were not significantly age-dependent. When IL-12 levels from the food-allergy group were compared with those from normal controls younger than 4 years of age, the difference remained significant (p = 0.001), ruling out an age-bias. The conclusions made in this study were that serum IL-12 and sCD30 showed different behaviors in children with food or pollen allergy. We found IL-12 and sCD30 levels in pollen-allergic patients that agree with the classical T-helper (Th) 1/Th2 paradigm of allergy. In contrast, serum IL-12 levels were increased in food-sensitized children, suggesting a different immunologic pathogenesis.     

Immunotherapy – risk/benefit in food allergy

Food allergy is a growing health concern in the westernized world with approx. 6% of children suffering from it. A lack of approved treatment has led to strict avoidance of the culprit food proteins being the only standard of care. Nowadays in‐depth research is conducted to evaluate the possible use of allergen‐specific immunotherapy (SIT) as an active therapeutic option for food allergy. Various routes of administration for the immunotherapy are investigated, including subcutaneous, oral, sublingual, and epicutaneous, and some appear to be successful in inducing a temporary tolerant state. Most research has been conducted with oral immunotherapy due to its efficacious and relatively safe profile. Increasing interest is dedicated to safer and more convenient approaches, such as sublingual and epicutaneous SIT; however, doubts exist about their possible capacity to induce temporary tolerant state and permanent oral tolerance. The high frequency of allergic adverse reactions of the various approaches and the inability to achieve permanent oral tolerance have highlighted the need of refinements in the strategies. A promising strategy for preventing IgE cross‐linking and thus enhancing safety of SIT, while still activating T cells, is the use of tolerogenic peptides. The implementation of such an immunotherapy approach has the potential of not only increasing the chance of achieving a permanent state of tolerance, but also improving the safety and tolerability of the therapy. Immunotherapy for food allergy is still not ready for the clinic, but current and upcoming studies are dedicated to collect enough evidence for the possible implementation of allergen‐SIT as a standard treatment for food allergy.     

Anaphylaxis after prick‐to‐prick test with fish

Skin prick testing is the diagnostic procedure for allergies and is considered to be safe. It is usually performed using the prick and the prick‐to‐prick method. Herein is described a pediatric case of anaphylaxis during prick‐to‐prick testing with raw fish in a patient who had consumed fish without any systemic allergic reactions beforehand, to illustrate that skin prick testing should be carefully planned and performed with caution in order to avoid potentially serious risks for the patient.     

Long‐term follow‐up of de novo allergy in pediatric liver transplantation – 10 yr experience of a single center

We conducted a study to clarify the incidence, clinical course, and risk factors of de novo allergies after liver transplantation. Ninety‐three patients who had been followed longer than one yr and who had no previous allergy history were included. Forty‐two patients (45.2%) developed de novo allergy. Of them, food allergy developed in 35 (37.6%). Respiratory allergy was observed in three (3.2%), and a patient (1.1%) had drug allergy. Fifty‐two (55.9%) of the 93 patients developed eosinophilia. The median age of patients with de novo allergy was 15 months (IR 11.3–20 months). De novo allergy developed five months after liver transplantation (IR 2.3–9.5 months) and lasted for 16 months (IR 8–34.5 months). Younger age at liver transplantation displayed statistically significant differences in development of allergy between allergy and non‐allergy groups. Twenty‐nine (69.0%) patients improved from allergy during the follow‐up period. No patient with de novo gastrointestinal allergy progressed to any respiratory allergy such as asthma. Older age at transplantation, EBV non‐risk, and CMV non‐risk had statistical significance in allergy improvement. Younger age at transplant predisposes to the development of allergy, while improvement of allergy is achieved more in older age.     

Anaphylactic reaction to lychee in a 12‐year‐old girl: Cross‐reactivity to latex?

There are very few case reports on allergic reactions to lychee in the literature – so far only in adults. We report on a 12-year-old girl who developed swelling of lips, pruritus, generalized urticaria and dyspnea 30 min after eating a raw lychee. A second event occurred after eating a piece of cake covered with a fruit cocktail. All other foods were well tolerated. In infancy the girl had suffered from atopic dermatitis, which disappeared in childhood; for the previous 2 yr she had presented with seasonal allergic rhinoconjunctivitis. Upon oral provocation, she developed restlessness, flush, generalized urticaria and inspiratory stridor 50 min after eating half a lychee. The diagnostic work up showed a clear positive skin prick test to raw lychee and specific immunoglobulin E (IgE) in serum to latex but not to lychee. In the cellular antigen stimulation test (CAST) carried out with lychee extracts in several concentrations, the same positive results could be found confirming an allergic reaction. Cross-reactivity of lychee to latex was shown by inhibition experiments using the UniCAP 100-system. In conclusion, it seems worthwhile considering the rare allergy to lychee in the case of unclear food-allergic reactions and lychee should be added to the list of foods cross-reacting with latex.