A sixty-six-year-old woman came fully frightened. She had been told that her rash could be mycosis fungoides, a rare form of malignant lymphoma. The diagnosis had been made on the basis of skin biopsy findings.

She related to us her eighteen-month history of a scaly, mildly itchy eruption. It had begun on her breasts, spreading later to her back, abdomen, and thighs. At first her condition had been called parapsoriasis, but a second skin biopsy suggested that the problem had become malignant, converting the diagnosis to mycosis fungoides.

Treatments had included cortisone preparations, both internally and externally, antihistamines, and the avoidance of bathing (which magnifies itch). Nothing had helped. She still had large red scaly patches on her trunk and thighs. We felt she had the benign parapsoriasis, and not the dreaded mycosis fungoides, which insidiously leads to skin tumors and eventually spreads internally.

Since there is no known cause of parapsoriasis, it is labeled “idiopathic.” A century of looking for causes of parapsoriasis had yielded no answers. It would have remained that way in our patient, but for our detective work. Actually, nothing blunts a doctor's zest for studying a patient more than a dermatosis known to be idiopathic.

But nothing occurs without cause, and elimination of the cause spells cure for disease. We, therefore, always zestfully hunt for a cause. Our most successful maneuver has been to look for foods, bugs, and drugs that might be incriminated.