الفهرس 
PAPULAR URTICARIAOnly 14 pages are availabe for public view
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Abstract
P
apular urticaria is a chronic allergic disorder characterized by the presence of recurrent pruritic papules or vesicles and varying degrees of local edema. The lesions are most commonly grouped in linear clusters and present on exposed areas, particularly extensor surfaces of extremities, with sparing of the genital, perianal, and axillary regions. Intense pruritis accompanies the eruption, resulting in excoriations, secondary infection, scarring, and permanent hyperpigmentation. Although the prevalence of papular urticaria peaks in children from 2 to 10 years old, it occurs occasionally in adolescents and adults.
Papular urticaria was attributed to many causes. It is now clear that papular urticaria is a result of a hypersensitivity reaction to bites from insects, such as mosquitoes, fleas, flies, bedbugs and different species of mites. The severity of the eruption and pruritis are related to the host response to the salivary or contactant proteins. Papular urticaria tends to be evident during spring and summer months. However, in some climates, this condition can affect children throughout the year.
Because of the large number of people affected by allergic reaction to many species of arthropods, we tried in this work to study the contribution of some common arthropods to the induction of papular urticaria using skin prick test.
The study was conducted on 50 patients clinically diagnosed as papular urticaria of different age groups and of both sex. The studied cases were subjected to complete history taking, clinical examination and skin prick testing. Skin prick test was performed for all the patients using standardized purified antigens of 4 common arthropods: fleas, mosquitoes, flies and house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae). Positive and negative control tests were included to assess normal skin reactivity for the person being tested. Photographs were taken before and after interpretation of results.
There was no observable significant age or sex predilection in our studied cases. Seasonal variation was apparent with the highest affection in summer months followed by spring. None of the patients reported history of severe local or systemic reactions and so there was no indication for immunotherapy.
Our study revealed that the most common arthropod linked to papular urticaria concerning our patients was house dust mite followed by mosquitoes. Lesions were mainly in the form of clusters covering legs, arms and trunks. We found that bronchial asthma was the main allergic disorder associated with papular urticaria in our studied cases, and thus further studies could be carried out to find out the relation between bronchial asthma and papular urticaria.
In conclusion, it is of major importance for the treatment and prevention of papular urticaria that the exact cause is identified. Skin prick test can be a step forward in the recognition of the major role of arthropods in inducing papular urticaria. Only if the eliciting insect is known can effective preventive measures be established, since habitat, behavior and exposure modes vary considerably among the arthropod classes. In addition, patients with systemic reactions to an arthropod should receive appropriate emergency drugs or a specific immunotherapy could be suggested for them after identifying the causative arthropod.