Pemphigus vulgaris is a non-contagious, chronic skin disease characterized by the formation of blisters in uninterrupted sequence, or more often in crops. Premonitory symptoms, such as fever, chills, loss of appetite, and nausea, may be present for a day or two before the first eruption and each successive outbreak. The lesions appear as irregularly disseminated, pin-head-sized vesicles that develop within hours into tense, hemispherical blisters, one-half to three inches in diameter. Their number varies from one or two to several hundred.
The lesions show no predilection for particular regions nor any tendency to occur in groups. They contain clear serum that turns to thick pus in two or three days; not until then does an inflammatory areola develop. Individual blisters persist two to eight days. They do not tend to burst, but dry to thin yellow crusts that fall off and leave light brown spots or no trace at all. While one crop is drying, new lesions appear; the course of the disease is thus prolonged for months or years.