Dyshidrosis

The characteristics of dyshidrosis are itchiness of the palms or soles, followed by the sudden development of intensely itchy small vesicles on the sides of the fingers, the palms or the feet, sometimes described as having a "tapioca pudding" appearance. The vesicles may develop in waves. The locations of the eruption may be symmetrical on the body, and redness is not usually present. File:DyshidroticDermatitisOnHandsLateStage.jpg|Advanced stage of dyshidrosis on the fingers File:Dyshidrosis.JPG|Palmar dyshidrosis File:Palmar dyshidrosis peeling stage.JPG|Advanced stage of palmar dyshidrosis on the palm showing cracked and peeling skin File:Dyshidrosis late stage.jpg|Advanced stage of dyshidrosis on the foot File:Rim of scale on plantar surface of thumb.jpg|Rim of scale on the palmar surface of the thumb from a resolving dyshidrotic flare ==Causes==

Whilst the exact causes of the condition are currently unknown, A number of studies have implicated balsam of Peru. Id reaction and irritant contact dermatitis are also possible causes. In 2005, researchers from Anhui Medical University and the Chinese National Human Genome Center, Beijing, theorizing that mutations in single genes could predispose the condition, ran a study of a Chinese family with the condition present across four generations via autosomal dominant inheritance. Their analysis of haplotypes within the family identified a locus for the condition on chromosome 18. == Diagnosis ==

Dyshidrosis is diagnosed clinically by gathering a patient's history and making observations. == Treatment ==

Avoiding triggers may be useful, as may be the application of a barrier cream or wearing of gloves. although this can be dangerous in the long term due to the side effect of thinning of the skin, which is particularly troublesome in the context of hand dyshidrosis due to the amount of toxins and bacteria the hands typically come in contact with. Antihistamines such as Fexofenadine may be used to help with the itching. and kill off superficial Staphylococcus aureus, but they can be very painful and undiluted may cause significant burning. Alitretinoin (9-cis-retinoic acid) has been approved for prescription in the UK. It is specifically used for chronic hand and foot eczema. It is made by Basilea of Switzerland (BAL 4079). == Epidemiology ==

A study of 20,000 randomly-selected individuals in Gothenburg, Sweden in 1988 found 2% of male respondents and 3% of female respondents to have dyshidrosis, and that it comprised 5% of cases of hand eczema of any type. A study of 6300 pediatric patients in Turkey in 2006 found 1% to have dyshidrosis. == History of classification ==

The condition was named dyshidrosis by the British dermatologist William Tilbury Fox in 1873, in a clinical lecture wherein he presented it as "a disordered condition of the sweat-follicles and the sweat-function... which is, as a rule, diagnosed as eczema, but is a separate and distinct affair... I have termed the disease , because nature seems to have a difficulty in getting rid of the secreted sweat, which remains to distend the follicles, and to macerate the tissues." His theory that the condition was related to sweat was soon observed as unproven in scholarly publication The condition had already been described clinically in a lecture in 1871 by Sir Jonathan Hutchinson, who had named it cheiro-pompholyx. Hutchinson's work was based on his observations, in 1864, of the same woman patient who Tilbury Fox would later describe in his own lecture. In 1875 Hutchinson published his book Illustrations of Clinical Surgery, describing the condition of "cheiro-pompholyx" without making reference to Tilbury Fox's work. This led to a dispute between the two dermatologists, played out in letters to The Lancet. Tilbury Fox was aggrieved that his reading of Hutchinson's lecture suggested it to imply Hutchinson had been the first to formally describe the condition. Hutchinson apologised, saying that he had been in too much of a hurry to publish to read Tilbury Fox's work, and being aware that Tilbury Fox had described it as a sweating disorder, he had considered it to be a different condition to the one he was writing about. In the same letter he chastised Tilbury Fox for claiming propriety over describing the vesicles as resembling "a sago grain", a comparison that he had also independently made, and noted that the subject of his lecture in 1871 had been his patient for several years before Tilbury Fox's lecture. After a paper by Dr. A. R. Robinson describing the condition, entitled "Pompholyx" and mentioning the dispute, was published in the Archives of Dermatology the following year, Tilbury Fox responded with a strident critique of Robinson's conclusions and accused him of having misrepresented the facts of the dispute. ==See also==