Brno, Czech Republic — One of the keys in better managing atopic eczema patients, especially those who experience flares of their disease and recalcitrant to standard therapy, is to identify and avoid the sensitizing agents that these patients come into contact with.
“Patients suffering from atopic eczema are known to have a predisposition to allergies, which very often include a slew of contact sensitizers. Dermatologists should always think of possible contact allergy and readily perform patch tests in every atopic eczema patient who does not show an improvement of their symptoms with the appropriate topical treatment,” says Eliska Dastychova, M.D., of the first department of dermatology and venereology, faculty of medicine, Masaryk University, St. Anne’s University Hospital-Brno, Brno, Czech Republic.
Dr. Dastychova and Dr. Miroslav Necas conducted a study in which 871 patients (628 female, 243 male) with atopic eczema were patch tested using the European standard series (ESS), selected adjuvant substances of dermatologic external preparations and cosmetic products, as well as selected natural substances, in order to identify the contact allergens that may be responsible for not only acute flares of atopic dermatitis, but also those cases recalcitrant to standard topical therapy. Standard patch-testing guidelines were followed.
Results
Results showed that the most frequent sensitizations found in the ESS were nickel sulphate, 14.7 percent; Peru balsam, 5.2 percent; fragrance mix, 4.6 percent; cobalt chloride, 4.4 percent; formaldehyde, 2.1 percent; and potassium dichromate, 2.8 percent.
The most frequent sensitisations to the adjuvant and natural substances included thiomersal, 13.9 percent; extract arnicae and extract chamomillae, 2.9 percent; propolis, 2.8 percent; alcohols adipis lanae, 2.4 percent; and bronopol, 2.2 percent.
Dr. Dastychova says that many of these agents cause the symptoms of atopic eczema to persevere, regardless of appropriate topical therapy. She found that 44.3 percent and 26.8 percent of patients demonstrated a clinical relevance of allergic reactions to the ESS, and adjuvant and natural substances, respectively.
Out of the 871 patients in the study, 430 patients (49.4 percent) demonstrated contact hypersensitivity to the allergens tested.
Risks
The frequency of contact sensitization in patients with atopic eczema does not differ dramatically from non-atopic patients. However, due to the disturbed skin barrier function in patients with atopic eczema that enables facilitated penetration of allergens through the skin, at the end of the day, atopic patients do run a higher risk of developing contact sensitizations.
“When treating atopic dermatitis patients, clinicians should avoid topical preparations containing natural substances which are often relatively strong contact sensitizers. Patients are often treated with topical corticosteroids, and sometimes contact sensitization to these corticoid substances may develop — most commonly to budesonide.
“Patch tests should be performed in all atopic eczema patients, particularly in those patients where even a slight suspicion of contact allergy comes in mind,” Dr. Dastychova tells Dermatology Times.
Prevention
Dr. Dastychova says that in many of the study patients where there was a proven contact allergy, the subsequent preventive measures (i.e., avoidance of the contact with the contact allergen) led to the improvement of their eczema.
According to Dr. Dastychova, if atopic eczema does not improve or even gets worse with appropriate topical treatment, the reason might be contact sensitization to the effectual or auxiliary (i.e., preservatives, emulsifiers or antioxidants) substances of topical preparations used for atopic eczema treatment or to the cosmetic products used by a patient with atopic eczema.
“Contact sensitization in patients with atopic eczema is considerable.
“The better patients with an atopic diathesis are informed about their sensitivities to contact allergens, the better they can avoid them and the easier it is for them to effectively treat their atopic eczema and avoid unwanted flares of atopic disease,” Dr. Dastychova says. DT
Disclosures: This work was supported by a grant project IGA of the Ministry of Health of the Czech Republic No. NK 9203-3/2007.
