Asthma, dust mites

Dust has been recognised as a trigger for asthma for many years and the allergens are present in the faeces of the house dust mite, of genus Dermatophagoides. They are members of the order Arachnida (close relatives of ticks and spiders). They live off human skin that has been shed and hence are present in bedding and carpets. Since they are not visible to the naked eye and are difficnlt to control, they can be overlooked as the canse of this distressing disease. They may also be a cause of perennial rhinitis and atopic dermatitis. 

The causes may include household dust, droppings from dust mites, and mold. Asthma-related illness resulted in over 100,000 children visiting a hospital and losing over 10 million school days. A very different kind of long-term disability results from childhood lead exposure. The US Centers of Disease Control estimated that over one million US children have elevated blood lead levels due to household exposures. 

A 23-year-old man, with a history of asthma, house dust mite allergy, and rhinoconjunctivitis, presented with acute respiratory symptoms. He was given oral cetirizine, inhaled salmeterol, and fluticasone propionate, and oral prednisone 40 mg/day for 1 week and 20 mg/day for 1 week. His asthma recurred when prednisone was withdrawn and he took oral prednisone 60 mg/day for 1 week and 40 mg/day for 1 week. He also took montelukast 10 mg/day. He then developed severe peripheral edema with a gain in weight of 13 kg. Prednisone was withdrawn and his edema resolved. Montelukast was continued. 

In 1990, effectiveness was well documented by Tari et al. [7] using sublingual dust mite antigens for 12-18 months. Allergic rhinitis and asthma symptoms improved in the children treated. There was a significant decrease in symptoms as well as medication use. In 1994, after 24 months of treatment, the same researchers found a decrease of specific IgE antibodies to dust mites [36],... 

Bousquet J, Scheinmann P, Guinnepain MT, Perrin-Fayolle M, Sauvaget J, Tonnel AB, Pauli G, Caillaud D, Dubost R, Leynadier F, Vervloet D, Herman D, Galvain S, Andre C Sublingual-swallow immunotherapy (SLIT) in patients with asthma due to house-dust mites A double blind placebo-controlled study. Allergy 1999 54/3 249-260. 

Tari MG, Mancino M, Monti G Efficacy of sublingual immunotherapy in patients with rhinitis and asthma due to house dust mite - A double blind study. Allergol Immunopathol 1990 18/5 277-284. 

SLIT studies focusing more on effectiveness in allergic asthma were done with house dust mites [23-27]. Three of these studies reported a significant improvement of clinical symptoms [24, 26, 27] while one study failed to disclose any statistical significant improvement of asthma symptom scores and... 

Hirsch T, Sahn M, Leupold W Double-blind placebo-controlled study of sublingual immunotherapy with house dust mite extract (D.pt.) in children. Pediatr Allergy Immunol 1997 8 21-27. Bahceciler NN, Isik U, Barlan IB, Basaran MM Efficacy of sublingual immunotherapy in children with asthma and rhinitis A double-blind, placebo-controlled study. Pediatr Pulmonol... 

Sublingual immunotherapy House dust mite Desensitization Asthma Rhinitis... 

Carefully selected patients with rhinitis, conjunctivitis and/or asthma caused by pollen, house dust mite or cat allergy. Immunotherapy is also indicated when asthma during the pollen season complicates rhinoconjunctivitis. 

The efficacy of subcutaneous SIT has been clearly shown in a metaanalysis of 43 double-blind placebo-controlled trials in allergic rhinitis as well as another meta-analysis of 16 double-blind placebo-controlled studies in asthma patients [13]. The mean clinical improvement was 45% reduction in symptoms and medication compared with placebo in rhinitis and 40% in asthma patients, which exceeds the effects of drug therapy. A recent meta-analysis also confirmed that asthma responds favorably to SIT [14], However, recently it could also be demonstrated that SIT is effective in patients with house dust mite allergy, allergic rhinitis and asthma [15]. Immunotherapy in these patients not only reduced rhinitis and asthma symptoms as well as rescue medication, but also had an impact on bronchial hyperreactivity over the 3-year follow-up period. 

Platts-Mills TA, Thomas WR, Aalbeise RC, Vervloet D, Champman MD Dust mite allergens and asthma Report of a second international workshop. J Allergy Clin Immunol 1992 89 1046-1060. 

Pichler CE, Helbling A, Pichler WJ Three years of specific immunotherapy with house-dust-mite extracts in patients with rhinitis and asthma Significant improvement of allergen-specific parameters and of nonspecific bronchial hyperreactivity. Allergy 2001 56 301-306. 

Atopy refers to the allergic sensitivity that certain individuals develop towards common and mostly innocuous environmental antigens such as dust mites, plant pollens and animal proteins. The condition of atopy generally manifests itself clinically in the form of asthma, hay fever, eczema or allergic rhinitis. The development of an atopic condition has been associated with the generation of predominately Th2 biased immune response to the particular allergen, and is thus often referred to as a Th2 based disease (Romagnani, 1994). 

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