SEASONAL BULLOUS DERMATITIS 



2205 



StaphylinidcB : — 



Pcdderus columbinus de Laporte, 1832. 

 PcBderus peregrinus Fabricius, 1801. 

 PcBderus cerebripundatus Epp (?). ^ 



CantharidcB : — 



Epicauta sapphtrina M.a.cklm, 1845, 

 Epicauta tomentosa Macklin, 1845. 



The seasonal occurrence is [due to the fact that the adult insects 

 are only present for a limited period in the year, the remainder of 

 which is occupied by the long and comphcated development. 



Symptomatology. — So long as the insect merely walks over the 

 skin, and is not irritated, it does no harm. If, however, it starts to 

 crawl up the arm, down the neck, or up the trousers, it is soon 

 annoyed by the clothing and excretes the blistering liquid. 



If only a small quantity of this fluid is ejected, then only a single 

 small bulla may form, but if the insect moves a series of these may 

 be produced. If, however, the blistering fluid is well rubbed into 

 an area, then an eschar forms, with considerable surrounding irri- 

 tation. Occasionally, instead of a series of blisters, one long 

 bhster may extend a considerable distance along the forearm or 

 down the back. 



Usually there are no immediate symptoms, and it is only after an 

 interval of twelve to twenty-four hours that an itching or burning 

 sensation, or even severe pain, invites attention to the affected area, 

 when the blister or blisters, varying in size and number, as already 

 stated, are to be found full of yellowish serum and situated on an ery- 

 thematous areola. 



As a rule the victim does not see the insect and may not remem- 

 ber one crawling on him, and he may be entirely at a loss to account 

 for the blisters. It is here that the difficulty of diagnosis arises in 

 that the practitioner may see only one or two cases, and at the 

 moment may not think about these insects. 



If pricked and carefully treated, they quickly vanish and cause 

 no further trouble; but if they burst, and are allowed to be rubbed 

 by the clothing, they become raw, very tender, and painful — a con- 

 dition which may last for days. 



More rarely a considerable portion of the blistering liquid ap- 

 pears to get well rubbed into one spot, and then a small white 

 eschar is formed which may be surrounded by an extensive in- 

 flammatory areola, with its surface raised above the central necro- 

 tic area and covered with numerous small red papules. The whole 

 region becomes very painful and tender, and some couple of weeks 

 elapse before heahng is completed, which generally takes place 

 without any cicatrization. Secondary septic infections are rare. 

 After being en evidence for some three to four weeks, the beetles 

 disappear and the epidemic ceases for the year. 



