Leprosy.—In nodular leprosy we have the appearance of macules of greatly varying size and shape with a tendency sooner or later to symmetry. They tend to appear and recur in association with febrile accessions and, even when they have become permanent spots, they show increased redness, infiltration and tension when there is fever.
The color is rather that of a sunburn and may be uniform or the center may be pale with copper-colored periphery. These spots appear by preference on face, backs of hands, buttocks, extensor surfaces of extremities and back. They may mark the location of later developing nodules. At first they are oily rather than scaly. We soon note a disappearance of hair within the spot. These spots soon tend to become anaesthetic. The tubercles of leprosy are usually of a reddish-brown color.
In nerve leprosy the spots tend to appear on parts of the body usually covered by clothing, as scapular region, shoulders, arms, thighs or buttocks. The outline is ovoid rather than round and the spots may at first be hyperaesthetic rather than anaesthetic, as they later tend to become.
In circinate eruptions we often note a pale center with brownish-red borders. These borders may be hyperaesthetic while the centers show anesthesia. Bilateral symmetry is more common in this than in nodular leprosy.
Besides the spots nerve leprosy may show blister-like lesions on backs of hands and feet especially in the region of the knuckles. Ulceration may follow.
Malaria.—The most common cutaneous manifestation of malaria is herpes labialis. This is more common in benign types than in malignant ones. Urticaria is next in frequency. Malaria has seemed to be the cause of certain cases of purpura simplex.
In attributing skin manifestations to malaria one must always have in mind the scarlatiniform, urticarial and erythematous rashes due to quinine used in treatment.
Urticarial Fever.—In Japanese schistosomiasis the earliest symptoms are the urticarial rash and fever.
Plague.—Rarely cases of bubonic plague may show a small vesicle marking the site of the flea bite. Areas of necrosis of the skin, which are really sloughing patches, and incorrectly designated “carbuncles,” may be noted, especially over the site of the buboes.