The answer is simple. In most cases, the biopsy is the missing piece of the puzzle.
A proper diagnosis of pityriasis rubra pilaris is based on the clinical observations of a dermatologist and the supporting report of a dermatopathologist.
A skin biopsy is part of the diagnostic process. The additional information obtained from the biopsy can help identify diagnostic clues that are invisible to the naked eye.
There are many skin disorders that mimic the symptoms of PRP, e.g., psoriasis and seborrheic dermatitis. Too often, the “official” diagnosis of PRP is delayed until additional symptoms appear or the treatment plan for the “wrong skin disorder” goes awry.
Editor’s note: Misdiagnosed with seborrheic dermatitis, I was prescribed an ever-increasing regime of prednisone over a six-week period that resulted in hallucinations and hospitalization.
Why have a skin biopsy? Answer: to get the right diagnosis.
Sources used in writing this post