Erythema Nodosum Leprosum (ENL): What You Need to Know

If you or someone you care for has leprosy and suddenly develops painful skin lumps, fever, or feeling generally unwell, this could be erythema nodosum leprosum (ENL). ENL is an inflammatory reaction that happens mainly in people with the lepromatous forms of leprosy. It’s not the bacteria acting directly, but the immune system overreacting. That makes symptoms come on fast and feel severe.

What it looks like

ENL often shows up as multiple tender red or purple nodules under the skin, usually on the arms, legs, and face. These nodules can come with fever, swollen joints, eye problems (like uveitis), nerve pain or worsening numbness, and general tiredness. Some people also get swelling in the hands and feet, or develop abscess-like areas. Symptoms can appear suddenly, then fade, and return—sometimes repeatedly over months or years.

Doctors usually diagnose ENL from the history and a skin exam. Blood tests often show inflammation (high ESR or CRP) and sometimes more white blood cells. A skin biopsy can confirm the inflammation under the fat layer (panniculitis) and help rule out other causes.

How it's treated

Treating ENL has two goals: control the inflammation now and keep future attacks down. The main immediate treatment is oral corticosteroids (like prednisolone) to calm inflammation and pain. For many patients, steroids work fast but need careful monitoring because of side effects when used long-term.

Thalidomide is one of the most effective drugs for ENL and often stops attacks quickly. But it causes severe birth defects, so it is strictly controlled and never used in pregnant women or women who might become pregnant. Other options include clofazimine (an anti-leprosy drug that also helps ENL), pentoxifylline, colchicine, and some immunosuppressants like methotrexate or azathioprine in stubborn cases. Severe or recurrent ENL cases may need specialist care and combination therapy.

It’s vital to continue standard multidrug therapy (MDT) for leprosy even during ENL—treating the underlying infection reduces future reactions. Supportive care matters too: pain relief, wound care for any skin breakdown, eye checks for uveitis, and nerve monitoring to prevent long-term damage.

If you suspect ENL, seek medical help quickly. Early treatment lowers the risk of nerve injury and long-term disability. Ask your healthcare team about pregnancy-safe options, long-term steroid plans, and how to spot relapse signs. With the right care, most people recover from attacks and keep complications to a minimum.