Arthritis changes the way joints look, and the visible signs depend entirely on which type of arthritis is involved. Some forms produce bony bumps on the fingers. Others cause dramatic swelling, skin redness, or changes in posture. About 21.3% of U.S. adults have diagnosed arthritis, and the condition shows up differently in nearly every case. Here’s what to look for across the most common types.
Osteoarthritis: Bony Bumps and Knobby Joints
Osteoarthritis is the most common form, caused by cartilage wearing down over time. In the hands, the hallmark visual signs are hard, bony lumps that develop around the finger joints. Lumps at the joints closest to your fingertips are called Heberden’s nodes. Lumps at the middle finger joints are called Bouchard’s nodes. Both are firm to the touch (they’re actual bone growth, not fluid) and can make the fingers look knobby or widened at the joints. Over time, the affected fingers may angle to one side.
In weight-bearing joints like knees and hips, you won’t see bumps, but you may notice other changes. Knees can develop a bowed or knock-kneed alignment as cartilage wears unevenly on one side. Swelling around the knee may come and go, giving it a puffy appearance. Hips with osteoarthritis don’t show much on the outside, but you might notice a shortened stride or a slight limp. On X-rays, osteoarthritis shows up as narrowed space between bones where cartilage used to be, along with bone spurs forming at the joint edges and increased bone density underneath the worn cartilage.
Rheumatoid Arthritis: Symmetrical Swelling and Deformities
Rheumatoid arthritis (RA) is an autoimmune condition, and it looks distinctly different from osteoarthritis. The earliest visible sign is typically soft, boggy swelling around the knuckles and wrists, usually on both hands at the same time. The skin over affected joints often appears flushed or slightly red and feels warm to the touch. This is true inflammatory swelling, not the hard bony enlargement of osteoarthritis.
As RA progresses without adequate treatment, the joints can develop characteristic deformities. The fingers may drift toward the pinky side of the hand at the knuckle joints, a pattern called ulnar deviation. Individual fingers can develop specific shapes: swan-neck deformity, where the middle joint hyperextends upward while the fingertip curls down, or boutonniere deformity, where the middle joint bends downward while the fingertip points up. The elbows may develop a permanent bend that won’t fully straighten. In the feet, the toes can curl upward at the base and bend downward at the tips, creating a claw-like or hammer toe appearance.
Some people with RA also develop rheumatoid nodules, which are firm lumps under the skin, most often near the elbows, forearms, or backs of the heels. These are rounded and flesh-colored, without the white discharge that can appear with gout deposits.
Psoriatic Arthritis: Sausage Fingers and Nail Changes
Psoriatic arthritis produces some of the most distinctive visual signs of any arthritis type. The most recognizable is dactylitis, often called “sausage digits.” Instead of swelling isolated to a single joint, the entire finger or toe puffs up uniformly, looking like a small sausage. This can affect just one or two digits, and it signals more severe disease that tends to cause permanent joint damage if untreated.
The nails offer another major visual clue. Psoriatic arthritis frequently causes nail pitting, which looks like tiny dents or divots scattered across the nail surface, as if someone poked the nail with a pin. In mild cases, you might see just a few pits on a couple of nails. In severe cases, the entire nail surface becomes rough and crumbly. The nail can also separate from the nail bed and lift upward, creating a gap underneath that may collect debris and turn yellowish or white. Many people with psoriatic arthritis also have visible psoriasis plaques (red, scaly patches) on the skin, particularly at the elbows, knees, or scalp.
Gout: Red, Swollen Joints and White Lumps
An acute gout attack is one of the most visually dramatic forms of arthritis. The classic presentation is a big toe that becomes intensely swollen, hot, and deep red or even purplish within hours. The skin over the joint looks stretched and shiny from the swelling. The redness and inflammation can extend well beyond the joint itself, sometimes making it look like an infection.
People with chronic or poorly controlled gout can develop tophi, which are deposits of uric acid crystals that accumulate under the skin. A tophus appears as a firm, roundish lump that can range from pea-sized to as large as a tangerine. They most commonly form around the fingers, toes, elbows, and the outer edge of the ear. Tophi have a distinctive feature that helps identify them: they sometimes develop a white head where uric acid crystite pushes toward the skin’s surface. In some cases, a tophus breaks open and releases a white, chalky discharge. This white coloring distinguishes tophi from the flesh-colored nodules seen in rheumatoid arthritis.
Ankylosing Spondylitis: Postural Changes
Ankylosing spondylitis primarily affects the spine, so its visible signs show up in posture rather than in the hands or feet. As the vertebrae gradually fuse together, the natural curves of the spine flatten out and the upper back rounds forward. Over time, this creates a noticeable hunched posture where the person has difficulty standing fully upright. The head may jut forward, and looking straight ahead can become difficult. In advanced cases, weakened vertebrae can develop compression fractures that worsen the forward curve further. From a distance, the posture change is often the most obvious sign that something is wrong, long before any joint swelling is visible.
Inflammatory vs. Degenerative: How to Tell the Difference by Looking
One of the most useful visual distinctions is between inflammatory arthritis (like RA, psoriatic arthritis, and gout) and degenerative arthritis (osteoarthritis). Inflammatory types make the skin over the joint look red, feel warm, and appear visibly puffy with soft swelling. The swelling is often worst in the morning and improves somewhat with movement. Osteoarthritis, by contrast, produces hard, bony enlargement rather than soft swelling, and the skin color over the joint usually stays normal. Redness and heat are hallmarks of inflammation. If a joint looks red and feels hot, that points toward an inflammatory or crystal-based arthritis rather than simple wear-and-tear.
What Arthritis Looks Like in Children
Juvenile idiopathic arthritis can be harder to spot visually because young children often don’t complain of pain. Instead, the signs tend to be behavioral. A child may limp first thing in the morning or after a nap, or appear unusually clumsy. You might notice a knee or ankle that looks puffy compared to the other side, or a reluctance to use one hand.
One important difference from adult arthritis is that some forms of juvenile arthritis cause eye inflammation that produces no visible symptoms at all from the outside. Left undetected, this can lead to cataracts, glaucoma, or vision loss. Children with juvenile arthritis need regular eye exams with an ophthalmologist even if their eyes look completely normal.
What Imaging Reveals
When visible signs alone aren’t enough, imaging fills in the picture. On a standard X-ray, osteoarthritis shows narrowed joint spaces (where cartilage has thinned), bone spurs at the joint margins, and sometimes fluid-filled cysts within the bone. Rheumatoid arthritis looks different on X-rays: instead of bone spurs, you see erosions where bone is being eaten away at the joint edges, along with soft tissue swelling around the joint. CT scans provide a more detailed view of bone changes and spurs. Ultrasound is particularly good at detecting fluid-filled cysts that form in osteoarthritic joints and can show inflammation in the soft tissues surrounding the joint in real time.
For most people, the combination of what a joint looks like on the outside, which joints are affected, and how the symptoms behave over time gives a strong indication of which type of arthritis is involved. Symmetrical soft swelling in the small joints of both hands points toward RA. A single hot, red toe suggests gout. Bony bumps at the fingertips with no redness suggest osteoarthritis. Swollen sausage-shaped digits with pitted nails point toward psoriatic arthritis. Each type has a visual signature, and recognizing it is often the first step toward the right diagnosis.