DY SID ROSES 



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History. — Bontius described the affection in his work, ' De 

 Medicina Indorurn'; Cleghorn in his book, 'Diseases of Minorca/ 

 identifies it with sudamina; he states that the term used in Minorca 

 to indicate the eruption was calor picante. Willan, Johnson (182 1) 

 and other Enghsh observers described it in India and other tropical 

 countries with the term Lichen tropicus. Armand in 1854 describes 

 it in his book, ' L'Algerie Medicale,' using the name Lichen miliar 

 pruriginosus ; he mentions that sea-bathing often increases the 

 severity of the eruption. Mestre, in Cuba in 1862, wrote a very 

 complete paper on the condition; he uses the term ' salpullido/ 

 In more recent times the eruption has been studied by Robinson, 

 Torok, Durham, and many others. 



etiology and Pathology. — Politzer considers the disease to be due , 

 to the obstruction of the flow of sweat brought about by the cells 

 of the epidermis swelling by imbibition from the excessive sweat. 

 Pearse considers it to be due to an acute distension of the sebaceous 

 glands by their own secretion. Robinson states that the inflam- 

 mation is about the sweat-pore, while, according to Torok, it has 

 nothing to do with it. In our experience, the inflammation is not 

 always about the sweat-pore. 



Durham believes prickly heat to be an infective disease, caused by a minute 

 actively motile amoeba; his results, however, have not been confirmed. 



Symptomatology. — This affection is extremely common in tropical 

 countries, especially in new arrivals. The eruption consists of small 

 pin-head papules, which may enlarge to the size of a millet-seed, and 

 even larger. The papules are generally conical, angry red, and often 

 occupy the orifices of the sudoriferous follicles; they are occasion- 

 ally topped by a small vesicle, the contents of which may later, 

 occasionally, become purulent. Besides the papules, roseola-like 

 spots are often seen; these in some cases may coalesce and form 

 large erythematous patches. Occasionally minute glass-like vesicles 

 of sudamina crystallina are also present. The eruption is found on 

 the parts of the body where the patient perspires most. It is very 

 commonly observed round the waist, the back, chest, arms, and 

 forehead; it may extend to the whole surface of the body, except, it is 

 generally stated, the palms and soles. In our experience, when the 

 eruption is general, the palms and soles also may be affected ; in such 

 situations, however, no papules are found, but only roseola-hke spots. 

 We would also call attention to another feature found in cases of 

 acute severe general prickly heat eruption: in several such cases 

 the oral mucosa and the fauces will appear acutely congested. The 

 congestion subsides on the disappearance of the cutaneous lesions. 



Diagnosis. — This is generally easy; from eczema it is distin- 

 guished by the greatly increased flow of perspiration, and by 

 the absence of any moist lesions during the whole course of the 

 malady. Our experience is, however, that in some cases true 

 eczema — especially of the papular type — develops on prickly heat 

 lesions. In cases of generahzed prickly heat, with roseola-like 



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