If you’ve had lymph nodes removed or irradiated, don’t put a heat pad on that limb or that side of your body.
Not on a swollen arm after breast surgery, not on a leg after groin or pelvic node surgery, and not on an arm that has never swollen but sits on the operated side.
This is one of the few places where our answer is simply no, so here’s the reasoning rather than just the rule.
Why heat is the wrong direction
Your lymphatic system drains fluid out of the tissues. Remove or damage nodes and that drainage capacity is permanently reduced on that side. Lymphoedema happens when the fluid arriving exceeds what the remaining system can clear.
Heat widens blood vessels and increases the fluid pushed into the tissues. On a limb with normal drainage that’s irrelevant. On a limb already at its ceiling, you’ve added to the inflow side of an equation that’s the problem.
It’s the same mechanism that makes heat wrong for varicose veins and swollen legs and for fresh injury swelling. Lymphoedema care guidance has long advised avoiding saunas, hot tubs and hot packs on an at-risk limb for exactly this reason.
Two risks stacked behind that one
Sensation is often altered. Axillary surgery frequently leaves numbness in the inner upper arm and around the armpit. Numb skin doesn’t tell you a pad is too hot, and by the time you notice, the damage is done. See who should not use a heating pad.
Infection is the complication that matters. A limb at risk of lymphoedema is a limb at risk of cellulitis, and a burn is a break in the skin. Standard advice for these limbs is to protect the skin from cuts, burns, insect bites and injections. A heat pad sits squarely in that list.
What helps instead
- A lymphoedema therapist. Compression garments fitted properly, manual lymphatic drainage, bandaging where needed. This is a treatable condition with a specialty built around it, and self-managing it with heat and hope is how people end up with a limb that’s harder to reverse.
- Movement. Muscle contraction is a significant part of what moves lymph. Gentle, regular, built up gradually.
- Elevation when resting.
- Skin care. Moisturise, protect from cuts and burns, treat any break promptly.
- Cool rather than warm if the limb aches at the end of the day.
Where heat is still fine
The rest of you isn’t off limits. A stiff lower back, a tight neck, a knee with morning stiffness, as long as you stay off the at-risk limb and the quadrant it drains into.
Two edges worth naming. After breast surgery that means keeping the pad off the chest wall, armpit and shoulder on the operated side, not only the arm. And if your neck and shoulder ache because one arm has been doing less, that ache is real and worth treating, but treat it on the other side and take the rest to a physiotherapist. See shoulder blade pain.
Cording, scar tightness and a shoulder that won’t lift after surgery all respond to treatment. Heat isn’t the tool, and the exercises are: after surgery: when is heat allowed? and frozen shoulder.
Get medical help the same day if…
- The limb becomes red, hot, tender or painful, or you feel feverish and unwell. Cellulitis in a lymphoedema limb needs antibiotics quickly, and people who’ve had it once are told to have a plan for the next time.
- Swelling increases suddenly rather than gradually
- You develop a burn, blister or any break in the skin on that limb
- The limb becomes painful in a way it hasn’t been before
And speak to your cancer team or a lymphoedema service if you notice a ring or watch getting tight, a heavy feeling in the arm, or clothing marking more on one side. Early lymphoedema is far easier to manage than established lymphoedema.
Clinically reviewed by: Nigel Chua (Hand Occupational Therapist) & Louise Yow (Physiotherapist). This article is general information, not a diagnosis. electricheatpad.com sells electric heat pads.
