IgE and IgE Receptors in ‘Allergic’ Skin Diseases
Immunomodulation and the Treatment of Hives and Eczema
Technische Universität München
Modern approaches in the management of hives and eczema
Johannes Ring, Markus Ollert, Ulf Darsow, Heidrun Behrendt
Urticaria (hives) and Eczema (atopic eczema, atopic dermatitis) represent the most common skin diseases, next to allergic contact dermatitis and exzanthematous drug eruptions. Urticaria can be classified according to kinetics into acute (less than 6 weeks) and chronic (occurring over more than 6 weeks). In the management of urticaria a 3 step schedule is recommended with basic (step 1), intense (step 2) and challenge test examination (step 3). If done properly, after elimination of relevant causal factors in a long-time observation, 80% of patients become symptom-free. Antihistamines are first-line therapy in acute urticaria, i.v., sometimes together with glucocorticoids. After adequate diagnostic work-up, nonsedating H1-antagonists should be given for a period of at least 4 weeks independently of the occurrence of skin lesions. In cases of autoimmune urticaria a positive autologous serum test ("Greaves test") is diagnostic, and immunomodulating treatment (cyclosporin, i.v. IG) or leukotriene antagonists have been used.
Eczema is an inflammatory chronically relapsing, non-contagious and extremely pruritic skin disease with a certain genetic background ("atopic diathesis") which is also common to allergic asthma and rhinoconjunctivitis. The management of eczema patients comprises a complex spectrum of activities aiming at distinct pathophysiological features, such as emollients, in trying to restore the disturbed epidermal barrier function, anti-inflammatory treatment with topical steroids or the new topical calcineurin inhibitors, UV treatment, antimicrobial strategies, and in severe cases systemic immunosuppression or climate therapy approaches. The role of allergy has long been controversial in eczema. However, using the "Atopy Patch Test" (APT) we proved that IgE inducing allergens can elicit eczematous skin reactions on uninvolved, untreated skin; most common elicitors are house dust mites, grass pollen, and animal epithelia, but also food allergens. APT has the highest specificity compared to skin prick test and IgE measurement. On the basis of allergy diagnosis, specific avoidance strategies are indicated. The use of allergen-specific immunotherapy (ASIT) in eczema is controversial. Some controlled trials have shown significant effects. The current state of the art regarding ASIT in eczema may be compared to its position in 1955 in respect to hay fever. For tertiary prevention, educational programs such as "eczema schools" have been developed and successfully evaluated in a multicenter national trial in Germany.
In the future, novel immunomodulatory approaches including anti-IgE, soluble IL4 receptors, or antibodies against other cytokines (anti IL5, etc) but also novel modes of allergen specific immunotherapy may enrich our therapeutic arsenal. The rapid progress in experimental allergology and dermatology has led to a new understanding of eczema subgroups and possibly will give rise to new therapeutic and preventive strategies.
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