The eruption in this disease consists of numerous small tumors of sebaceous gland origin, varying from pin-head to split-pea size and from normal flesh color to yellowish red or brown. The growths are most numerous about the naso-labial folds, but occur scattered over other parts of the face, especially upon the nose, chin, and cheeks. They are least numerous on the forehead, but here the lesions are apt to be large. The tumors are slightly firmer than normal skin. They are rounded and usually discrete except when they are very closely aggregated, in which case they may partially coalesce like the drupelets of a mulberry. Ocassionally, and especially when their color is bright red, the little growths are marked on the surface by a fine network of dilated capillaries; nevertheless the color is little altered by pressure. Their surface is generally smooth but may be slightly rough or warty.
In many cases the growths are present at birth or appear soon afterwards. At puberty they increase considerably in number and size. After a time the condition stabilizes. The patients are often mentally deficient, and the disease is met with most frequently among children in imbecile asylums.