The condition described by Unna as peculiar to seamen is also found in those who are much exposed to the sunlight, especially where the air is very dry. As it is fairly common in the western part of the United States among those following agricultural pursuits, it has been aptly named "farmer's cancer." The condition commences with a deep bronzing of the skin, later the cutaneous covering becomes dry and rough and minute keratoses develop.
Hyde* has thoroughly considered this type of dermatosis, showing how frequently rodent ulcers develop upon these keratotic patches. More recently Lawrence* has called particular attention to the prevalence of this disease in Australia. Lawrence states that out of 6,000 consecutive cases at his clinic 1.8 percent, or 108 cases, showed this condition, a figure greatly in excess of the prevalence of rodent ulcers at the European skin clinics. He attributes the condition to the great amount of sunshine and the low relative humidity of the atmosphere.
The treatment is the same as for "sailor's skin".