Thalidomide in Dermatology
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Direct answer
Thalidomide in dermatology is an immunomodulatory drug used mainly for erythema nodosum leprosum, and occasionally for refractory prurigo nodularis and mucocutaneous Behcet disease. Its use is limited by severe teratogenicity, which causes limb and other malformations when taken in pregnancy, and by dose-related peripheral neuropathy. Prescribing is restricted under controlled distribution, and pregnancy prevention is required for every patient who could conceive.
What you must remember
- Mechanism: inhibits tumour necrosis factor alpha production and has immunomodulatory and anti-angiogenic effects.
- Erythema nodosum leprosum: a type 2 leprosy reaction, where thalidomide is used when steroids are ineffective or cannot be tapered.
- Other uses: refractory prurigo nodularis and mucocutaneous Behcet disease, by specialist decision.
- Teratogenicity: severe limb and other malformations, so use requires pregnancy exclusion and reliable contraception.
- Peripheral neuropathy: dose-related sensorimotor neuropathy, often irreversible, which prompts stopping the drug.
- Thromboembolism: venous thrombosis and pulmonary embolism are increased, so prophylaxis is considered in high-risk patients.
- Sedation and constipation: common, particularly early in therapy.
- Controlled prescribing: registration, restricted distribution and pregnancy prevention rules apply to every prescription.
A safe sequence for a teratogenic drug
Thalidomide is justified only when its indication is clear and its risks are managed from the first prescription. The steps below set out what is required at each stage.
- Confirm the indication: use it for erythema nodosum leprosum that is steroid-dependent or steroid-resistant, or for refractory prurigo nodularis after other options have failed.
- Exclude pregnancy: test before each prescription, and counsel every patient who could conceive on reliable contraception.
- Register the patient: enrol in the controlled distribution scheme and record counselling, as national rules require.
- Counsel on neuropathy: teach the patient to report numbness, tingling or weakness, and stop the drug if these appear.
- Prevent thrombosis: consider thromboprophylaxis for patients with added risk factors, such as immobility or cancer.
- Review and taper: use the lowest effective dose, reassess need at each visit and stop when the indication has resolved.
The benefit in erythema nodosum leprosum is real, but the teratogenic risk is severe enough that every step must be documented. Missing one step can cause harm that cannot be reversed.
Where the exam tries to catch you
Thalidomide questions test the order of indications, the pregnancy rules and the neuropathy warning.
- Trap: choosing thalidomide first for acute erythema nodosum leprosum Correct: corticosteroids are the usual first-line for severe acute reactions, especially with neuritis, which thalidomide does not treat. Thalidomide is reserved for steroid-dependent, recurrent or resistant cases, and is avoided in women who could conceive.
- Trap: checking pregnancy status once at the start Correct: testing and contraception are needed throughout therapy, not only at the first visit.
- Trap: continuing the drug when numbness appears Correct: neuropathy is dose-related and often irreversible, so the drug is stopped or reduced.
Frequently asked questions
Why is thalidomide restricted in dermatology?
Thalidomide is restricted because it causes severe birth defects when taken in pregnancy, including limb malformations. Its peripheral neuropathy is also dose-related and can be permanent. Prescribing therefore requires registration, pregnancy prevention and controlled distribution.
What is thalidomide used for in leprosy?
Thalidomide is used in leprosy mainly for erythema nodosum leprosum, a type 2 reaction. It is reserved for patients whose reaction is steroid-dependent or steroid-resistant. The same teratogenicity precautions apply as in other settings.
How is thalidomide neuropathy recognised?
Thalidomide neuropathy presents as distal numbness, tingling or weakness in the feet and hands, and it is dose-related. It can be irreversible, so symptoms prompt stopping or reducing thalidomide. A nerve examination should form part of routine monitoring.
Why does thalidomide increase the risk of blood clots?
Thalidomide increases the risk of venous thromboembolism, including deep vein thrombosis and pulmonary embolism. The exact mechanism is not fully established. Thromboprophylaxis is considered for patients with additional risk factors such as immobility or cancer.