DermaDiagnosis
Retired Tour Guide Intends to Maintain Her Tan
A 60-year-old woman is seen for complaints of skin changes on her neck that have slowly become more noticeable over a period of years.
ANSWER
The correct answer is soft corn (choice “c”). They are caused by bony friction and almost always found between the fourth and fifth toes.
Soft corns are often mistaken for warts (choice “a”). But warts don’t present as painful, macerated lesions between the toes.
Morton neuroma (choice “b”) is actually a neurofibroma, not a virtual tumor. It is usually found on the plantar forefoot between the second and third toes.
Interdigital fungal infections (choice “d”) often develop between the fourth and fifth toes and are often macerated. However, they do not take the form of lesions and do not hurt.
DISCUSSION
Soft corns are known in podiatric circles as heloma molle but are sometimes called kissing corns because they’re caused by friction between bony prominences on the fourth and fifth phalanges, which rub together with every step. Normally, these toes are hourglass shaped, but in patients prone to develop soft corns, the proximal bases of the toes are too wide. The type of shoe the patient wears can be an important factor as well, especially when high heels and/or narrow toe boxes are involved.
The treatment of soft corns can be nonsurgical—sometimes as simple as separating the toes with a tuft of lambswool. However, surgical intervention is often required. In such cases, the head of the proximal phalanx is cut and removed to make the adjacent bones more parallel. Occasionally, the skin is so damaged that it too must be removed and the toes sewn together.
Removing corns with chemicals, shaving, or excision provides no lasting relief, since these methods do not address the underlying structural issues.
Hard corns, also known as heloma durum, tend to develop on the dorsal aspect of the fifth toe secondary to pressure from shoes. Changing the type of shoe worn is one solution, but often, as with soft corns, the underlying bony prominence must be addressed.
There is a third type of corn, the periungual corn, which develops on or near the edge of a nail. These corns are often erroneously called warts.
This patient was referred to a podiatrist, who will likely solve the problem. There is no topical product that can help, and nonsurgical approaches will provide temporary relief at best.
