This 46-year-old man’s skin disease has gotten so serious that he is essentially disabled. The problem started about six months ago, with joint pain that particularly affected his left ankle. Now, his hands are fissured and swollen to the point that he is unable to button his shirt or hold a fork. He is referred to dermatology by his attorney, who is helping him pursue possible disability benefits, for evaluation and treatment.
He has been seen by a variety of primary care providers, who have collectively prescribed topical triamcinolone 0.1% and several antifungal medications, including a two-month course of oral terbinafine. When those failed, he was treated with prednisone; at the start of the three-week course, there were signs of improvement but by the end, his hands were worse than ever.
The dorsal and palmar surfaces of the patient’s hands are covered with thick, white scales atop salmon-colored erythematous bases. Multiple fissures and marked edema can be seen. Seven of 10 fingernails are dystrophic, yellowed, and thickened.
The patient’s elbows, knees, and upper intergluteal area show less impressive involvement.
There is marked tenderness on palpation of the left Achilles insertion, made worse by dorsiflexion.
What is the diagnosis? DISCUSSION
Psoriasis can affect one or more areas, typically the hands, scalp, genitals, or feet. When it’s focused in one area, as in this case, it can be baffling to diagnose; sometimes it’s hard to see the forest for the trees. But because the condition affects almost 3% of white Americans, you’ll see it regularly—if you’re looking for it.
Nearly 25% of patients with psoriasis eventually develop psoriatic arthritis (PsA), which not only affects the joints but also can cause complications such as enthesitis, or inflammation of the entheses (the sites of insertion of the tendon into bone; eg, the Achilles). This can be confused with plantar fasciitis, which this patient had been previously diagnosed with.
This diagnosis could have been proved or disproved by a KOH prep (which would have shown evidence of fungal disease) or a biopsy (which would have shown fused rete ridges, microabscesses at the papillary tips, hyperkeratosis, and parakeratosis). Providers should first establish a firm diagnosis to dictate effective treatment. In this case, a visual diagnosis was possible.
Given the severity of the problem, the patient was started on a biologic; he showed vast improvement within a week. He was referred to rheumatology for evaluation and management of PsA, and the severity of his disease was communicated to his attorney.
TAKE-HOME LEARNING POINTS
- In some cases, psoriasis can be isolated to the hands, feet, genitals, or scalp, complicating detection of the condition.
- Almost 25% of patients with psoriasis develop psoriatic arthritis (PsA), which can manifest with dactylitis, arthritis, or enthesitis.
- Left untreated, PsA is potentially debilitating.
- Establishing a firm diagnosis with KOH prep or biopsy will dictate effective treatment.