2154 



DERMATITIS VENENATA 



naraceae, 'the Euphorbiacese, the Leguminosae, the Malvacese, the 

 Rubiaceae, the Rutacese, the Tropseolacese, and the Urticacese, the 

 genera and species of which are indicated above. 



II. Personal Idiosyncrasy. — When the poisonous principle is 

 contained in the juice of cultivated plants, the poisoning is largely 

 met with among gardeners, florists, and people associated with 

 plants in some way; when, however, the poisoning is due to a 

 principle contained in some special hairs of a plant, whether 

 cultivated or not, it is obvious that anyone may be affected ; and 

 when it is due to principles contained in the dust from dry 

 wood, it is also obvious that carpenters and persons who cut or 

 saw this wood will be most liable to be affected. 



With regard to the first series of cases, in our experience, 

 there can be no doubt that some people are more liable to the 

 affection than others, and it would appear that certain people 

 suffering from any form of seborrhoea or allied condition, no 

 matter how mild, are especially liable to be troubled by dermatitis 

 venenata. 



As stated in the previous editions of this book, we should not be surprised 

 if, in the future, it will be found that certain forms of dermatitis venenata 

 are due in reality to some parasitic micro-organisms living in the plants or 

 woods, and which get inoculated. The fact that, for instance, satin-wood 

 dermatitis appears several weeks after handling the satin-wood sawdust is 

 rather in favour of there being some contagium vivum which requires some 

 time to develop and multiply sufficiently to cause symptoms of disease. 



III. Confirmatory Test. — The crucial aetiological test is to remove 

 the patient from the district in which the plant grows, to cure his 

 dermatitis, and then, after a lapse of time, to test him experimentally 

 with the suspected plant, which, if the genuine causal factor, should 

 reproduce the eruption. 



IV. Active Principle. — Unfortunately at present hardly anything 

 can be said upon this subject. We know that drugs like quinine 

 can cause eruptions, and therefore we conclude that quinine is 

 the active principle causing the eruption produced by boiling cin- 

 chona bark; but with regard to the majority of the plants, we are 

 entirely or almost entirely ignorant of the Ichemical nature of the 

 active principle. 



Symptomatology. — Sometimes the symptoms consist merely of 

 itching, with or without an erythematous blush. At other times 

 there may be marked erythema, with oedematous swelling in the 

 affected part, which is often the face or the hands, or both. In more 

 severe cases a true dermatitis may be present with papules, vesicles, 

 or pustules, with or without such general symptoms as fever and 

 enlargement of the local lymphatic glands. 



The onset is generally sudden, and the affected person may pre- 

 viously have been in excellent health. The termination is in quick 

 recovery, especially if the causal agent is removed. 



Diagnosis.— The ease presents the ordinary appearance of an 

 acute dermatitis, and it requires patience and acumen to trace 

 this to its correct cause. 



