Authors' reply

Kiran V Godse

 Shree Skin Centre, 21 and 22, L Market, Sector 8, Nerul, Navi Mumbai - 400 706, India

Correspondence Address:
Kiran V Godse
Shree Skin Centre, 21 and 22, L Market, Sector 8, Nerul, Navi Mumbai - 400 706
India

Sir,

I wish to thank Dr. Pise and colleagues for showing interest in the article ′Diagnosis of delayed pressure urticaria′ (DPU). I also thank them for discussing in elaborate detail the differential diagnosis of delayed pressure urticaria. However, much as they suspect my diagnosis of DPU, I assure them that the cases being reported are neither dermographism nor delayed dermographism. Patients with DPU frequently demonstrate delayed dermographism (i.e. a late-onset linear whealing response to a frictional stimulus). Some investigators consider delayed dermographism to be a manifestation of DPU.[1] Because not all patients with DPU have delayed dermographism, it can be considered as a separate disorder in some cases. The incidence of DPU varies depending on the dermatology department from which it is reported.[2] There are also intermediate and delayed forms of dermographism (interpreted by someone to be synonymous with DPU) that develop more slowly and can last several hours to several days.[3]

The time of onset of lesions after a pressure stimulus to the skin varies. In one series, swelling appeared as early as 30 minutes after pressure and as late as nine hours after pressure (mean onset of swelling, 3.5 hours).[4]

There is no standard method of pressure testing. A positive response after any form of pressure challenge consists of the appearance of palpable lesions after at least 30 minutes. Because most positive responses occur at six hours, observers usually read pressure tests at six hours.[2]

Our study had taken visible and palpable swelling at 30 minutes and at six hours as positive test.[5] In our study we have tried to keep most parameters constant like two kg weight, 100 mm of mercury pressure and standard blood pressure cuff. We agree with the author that this is a crude method of testing for delayed pressure urticaria. We devised this method considering a common practicing dermatologist in the clinic, as existing instruments can be used in this test except two kg weight, which is easily available at a grocery shop. We could not do histopathology studies as the patients refused to undergo biopsy. Moreover, the histopathologic findings stated as specific for DPU by Dr. Pise and colleagues are seen in most cases of urticaria. As for validation of the method by comparing with a dermographometer, I would appeal to Dr. Pise and colleagues that coming from a well-equipped institute, they are in a better position to undertake this project. To sum up, I submit to my learned colleagues that instead of criticizing a novel idea based on suspicions, please try out the simple method suggested by me for demonstrating DPU, compare it with other methods and then report the findings in a scientific communication.

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