PARASITES AFFECTING THE SKIN 23 
present determines to some extent the symptoms pro- 
duced. 
Symptoms in the Dog.—-There are two types of fol- 
licular mange commonly seen in the dog : 
1. Pustular type (see also Appendix I.). 
2. Squamous type. 
Follicular mange usually begins at the head, in the 
neighbourhood of the eyes, and extends to the ears, 
sides of the face, and forehead. It then appears on the 
feet and legs, especially inside the elbows, and gradually 
extends over the whole body. The first symptom 
noticeable is the presence of patches denuded of hair. 
The skin is hot and usually of a peculiar purple tint. 
Its surface shows a varying number of small papules 
and pustules. As the patches increase in extent, the 
skin thickens and becomes puckered into folds. These 
are most apparent on the head, and are especially 
noticeable in bulldogs, in which the skin becomes one 
mass of wrinkles. The bare patches now take on a 
dark slaty-grey colour, and the skin emits a most 
unpleasant penetrating doggy odour. If the pustules 
are squeezed, a small core of pus escapes, and this, if 
examined microscopically, is found to contain a large 
number of parasites. There is very little pruritus, and 
the dog seldom scratches, but more often shakes the 
body (formication), very much as a dog does when 
leaving the water. The skin becomes dry and fre- 
quently cracks, leaving fissures, from which a small 
quantity of blood may ooze. It is not uncommon to 
find one side of the head much swollen in an advanced 
case from subcutaneous cedema. This is more often 
observed in bulldogs. 
In the squamous type of the disease there are few or 
no pustules. The eyelids are most commonly affected, 
especially in Poms and small dogs, but the whole body 
