Types, Symptoms, and Treatment
Like psoriasis and PsA elsewhere on the body, psoriatic disease in the hands and feet can cause itchy, scaling, reddened skin plaques and painful, swollen joints. Specific types and symptoms of hand and foot psoriasis and PsA, however, can also cause less-familiar skin and joint issues.
Palmoplantar psoriasis, plaque psoriasis on the feet or hands, affects about 40 percent of people with plaque psoriasis, who often don’t have much skin disease elsewhere. As noted, its substantial effects on function and quality of life mean dermatologists typically use advanced medications to control symptoms. Treating certain types of palmoplantar psoriasis is still challenging, despite the rapidly expanding list of medications for psoriasis and PsA. Often, palmoplantar psoriasis doesn’t respond as well to treatment as does psoriasis on other parts of the body.
Most biologics, which work by targeting specific proteins that turn up inflammation in psoriatic disease, such as tumor necrosis factor (TNF) or interleukin-17 (IL-17), have some effect on certain people with palmoplantar psoriasis.
No one treatment works for everyone, and people with palmoplantar psoriasis may have to try several medications or combinations of treatments to relieve symptoms. Gary Bixby, for example, didn’t get better with either a TNF or an IL-17 inhibitor. The third biologic he tried blocks another interleukin protein, IL-23, and, three months after his first injection, he’s getting better results.
“I’m seeing improvements in my fingernails and the plaques on my body, which I didn’t get with the first two biologics. I’m cautiously hopeful,” he says.
Palmoplantar pustular disease, or pustulosis, affects about 5 percent of people with psoriasis. It shows up as small, pus-filled blisters on reddened, tender skin. It can also cause painful cracking
Biologics can sometimes make pustular disease worse, says Duffin, so dermatologists may decide to begin treatment with a traditional disease-modifying antirheumatic drug (DMARD) such as methotrexate or cyclosporine.
“There are also new medications in development, specifically anti-IL-36 biologics, that could be a good treatment pathway for pustular psoriasis,” says Duffin.
Psoriatic nail disease can cause a host of symptoms in both the nail bed and the matrix, the area where fingernails and toenails start their growth. These include pitting, crumbling, thickening, discoloration, white or reddish spots, and separation of the nail from the nail bed (called onycholysis). None of these symptoms is specific to nail psoriasis, however, and some people have both nail psoriasis and nail fungus.
All this can make nail disease difficult to diagnose, says Duffin.
“If you have pitting, for example, you could have vitiligo or eczema instead of psoriasis,” she explains. (Vitiligo is a disease that causes skin, or sometimes hair, to lose its natural color.) “Sometimes, psoriasis patients are concerned about normal nail features, such as ridging or brittleness, that aren’t psoriasis.”
When the cause of nail symptoms isn’t clear, dermatologists look for signs of psoriasis elsewhere on the body. They may also look at a nail clipping under a microscope to distinguish one condition from another.
Once dermatologists understand what’s going on in the nails, they can decide how best to treat them. “All biologics have some data showing they can work better for nails than traditional DMARDs, but there is still no one slam-dunk treatment,” says Duffin, who notes that it can take months to learn whether a treatment is improving nail symptoms.
“It takes three to six months for nail to regrow entirely, so patients need to be on a treatment continuously for that time for us to know whether it’s working,” she says.
Nail psoriasis is also a risk factor for PsA, and when it occurs with other symptoms, may prompt a referral to a rheumatologist, who can evaluate you for joint disease.