What's Behind Black Swollen Knees? Pictures and Causes

Understanding Black Swollen Knees

Seeing a black or darkened swollen area on your knee can be alarming. However, it's often not as serious as it appears. In many cases, the dark or black color is caused by broken blood vessels or bruising resulting from injury or strain. Other common culprits behind knee swelling and discoloration include arthritis flares or skin conditions like eczema or psoriasis. Let's explore the common causes of black swollen knee spots and when to seek emergency care.

Bruising

Bruises occur when small blood vessels under the skin tear from impact and blood leaks into surrounding tissues. As the blood gets metabolized and cleared away over days or weeks, it turns from red, to purplish-black, to green, yellow and brown. The darker color often concentrates around the edges.

Common knee injuries leading to dark bruising include:

• Falling directly onto the knees
• Forceful blows during sports or accidents
• Knee strain from overuse, improper movement or weakness

Bruises are usually harmless, but seek prompt medical treatment if they result from major trauma or accompany severe pain, joint instability or rapid swelling.

Hemarthrosis (Bleeding into the Joint)

Hemarthrosis happens when an injury causes significant bleeding into the fluid-filled joint space in the knee. It shows up as tense swelling that turns black and blue over hours or days. Causes include:

• A torn ACL or meniscus knee injury
• Fractures of bones around the knee joint
• Ruptured popliteal cyst behind the knee

Seek immediate medical help if you suspect internal knee bleeding. Rest, ice, compression, elevation and diagnostics should happen promptly to assess severity and avoid complications.

Cellulitis Skin Infection

This bacterial skin infection provokes swelling, redness, warmth and discoloration of the skin. When cellulitis impacts the knee area, it often arises after minor cuts or injuries to the leg. The swelling can spread rapidly and the skin takes on a shiny, inflamed appearance ranging from pink to dark red or purple.

Untreated cellulitis can enter the bloodstream, so prompt antibiotic therapy is key. See your doctor right away if a skin infection is suspected, especially if you have chills, fever or increasing pain.

Underlying Causes of Knee Bruising and Swelling

In some cases, black and blue discolored knees result from underlying health conditions or age-related changes. Being aware of these other potential reasons helps guide appropriate evaluation and treatment.

Arthritis Flare-Ups

Those with arthritis are prone to episodic flares marked by painful inflammation affecting multiple joints like the knees, fingers, hips and spine. In osteoarthritis, the cushioning cartilage breaks down over years of wear-and-tear. The resulting bone-on-bone friction leads to swelling, stiffness and alterations in gait that strain the knees.

Rheumatoid arthritis causes similar problems through inflammatory processes. Flares seem to happen randomly but may get triggered by overdoing activity, stress or certain medications. Applying ice packs can ease the swelling and discoloration until medications provide relief.

Gout Attack

This form of inflammatory arthritis arises from excess uric acid accumulation in joints. Periodic severe flares feature red, shiny, extremely painful swelling often affecting the big toe, ankle, knee or wrist joints. Ice, rest and anti-inflammatories help lessen these attacks.

Dark purple skin discoloration can accompany gout flares around major joints like knees. Managing the root cause requires diet and lifestyle changes to prevent attacks.

Skin Disorders

Certain inflammatory skin conditions also manifest with darker discolored patches and swelling. Eczema, psoriasis and ichthyosis commonly impact joints including the knees, elbows and hands along with flaking, itchy rashes elsewhere.

Allergies, irritants, genetics and stress exacerbate these disorders. Judicious moisturizer use, anti-itch creams and other treatments aim to reduce incidence of rashes and lesions.

Poor Circulation

Insufficient blood flow to the lower legs can make the area appear bruised and swollen. Venous disease, diabetes and heart conditions often underlie circulation troubles. Elevating the legs periodically, wearing compression socks and staying active improve flow.

Seeking treatment for the root cause is key, as poor blood return from the lower body stresses veins and leads to further swelling issues over time if unaddressed.

When to Seek Emergency Knee Treatment

While most instances of black and blue swollen knees eventually heal with self-care, some scenarios demand emergency medical attention. Seek help without delay if you have:

• Sudden inability to bear weight on the leg
• Joint instability, falling or inability when walking
• Suspected knee fracture
• Significantly worsening pain and rapidly spreading bruise
• Symptoms of infection like fever, confusion or foul odor

Only a doctor can properly evaluate the severity of internal derangements versus more benign bruises. When in doubt, err on the side of caution, as some knee problems worsen drastically without prompt care.

Relieving Knee Pain and Swelling at Home

For garden variety knee strains and bruises, home care goes a long way towards relief and healing. Methods include:

• Rest - Avoid activities that aggravate pain and swelling.
• Ice - Applying ice packs intermittently constricts blood vessels to reduce internal bleeding and inflammation pain.
• Compression - Wrapping an elastic bandage around the knee limits swelling.
• Elevation - Prop up the leg above heart level so gravity pulls fluid away from the knee.
• Pain relievers - Over-the-counter meds like ibuprofen or acetaminophen help alleviate discomfort.

With diligent at-home care, minor knee contusions and strain gradually resolve over days to weeks. But see your doctor if problems persist beyond 10-14 days without improvement.

Preventing Knee Injuries

While bruises and strains sometimes arise unpredictably, building strong flexible leg muscles safeguards the knees and reduces injury risk. Helpful tactics include:

• Low-impact exercise like swimming, cycling and elliptical workouts
• Leg strengthening moves targeting quads, hamstrings and glutes
• Gentle stretching following workouts and as part of a cool-down
• Good shock-absorbing shoes for impact sports like running
• Proper knee alignment and biomechanics during demanding activity
• Joint supplements like glucosamine and chondroitin to nourish cartilage

By keeping your knees strong and balanced overall, you help prevent the strain that progresses into painful swelling episodes down the line.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.