A lump under the armpit is a good indicator that you have a swollen lymph node. In most cases, lymph nodes swell as they fight bacterial and viral infections. An injury on your hand or a nearby location could cause the lymph nodes under your armpit to swell.

Your lymph nodes could also swell if you have paroxysmal nocturnal hemoglobinuria (PNH). According to Susan McBratney PhD, lumps caused by PNH are generally painful, especially when touched.


PNH is an extremely rare disease that causes red blood cells to disintegrate. This happens because people with this disease lack an important gene called PIG-A. As a result, their red blood cells break down and lose hemoglobin. In fact, this is one of the symptoms associated with PNH (red blood in urine) and medical experts call this condition hemoglobinuria. Take note red blood cells play an important role in one’s health such as transporting oxygen to various parts of the body. They also contain iron, which the body requires to stay healthy and function properly. Other PNH symptoms include:

  • Back and abdominal pain
  • Headaches
  • Shortness of breath
  • Fatigue


Some swollen lymph nodes are harmless and usually resolve within a few days. Nevertheless, you should seek medical attention if a lump under your armpit persists for more than one week. Your doctor will examine the swollen lymph node, evaluate your medical history, and carry out tests that he/she feels are necessary to diagnose your illness. Depending on the outcome of this medical examination, your doctor may prescribe iron rich foods and vitamins to help increase your body’s red blood cells. Such foods include:

  • Bananas
  • Eggs
  • Whole grains.
  • Dark leafy greens
  • Nuts
  • Mangos
  • Avocadoes

Additionally, patients should also ramp up their intake of vitamins B2, B3, and B12, according to health experts (newhealthguide.org). Other treatment options include prescription of immune suppressants to halt the breakdown of red blood cells, blood transfusions, thrombolytic therapy, and bone marrow transplants.


In summary, if you develop a lump under the armpit, you should seek medical attention if it keeps growing for more than a week because you could be suffering from PNH. Doctors generally prescribe anticoagulation drugs and immune suppressants to treat swollen lymph nodes associated with PNH.