Home » Dermatology » How methotrexate has come to be a misunderstood skin therapy

Dr Tom King

Consultant Dermatologist, Sheffield Teaching Hospitals

Patients with inflammatory skin conditions may be prescribed a long-term treatment called methotrexate. A consultant dermatologist busts some myths surrounding the drug.

If you have an inflammatory skin condition such as psoriasis or eczema, you may be prescribed a drug called methotrexate. It is long-established but sometimes misunderstood, notes Dr Tom King, Consultant Dermatologist at Sheffield Teaching Hospitals.

“Methotrexate works as an immunosuppressant medication and has been widely prescribed by dermatologists since the 1960s to improve some inflammatory skin conditions — and with notable success,” he says. “For example, it can be extremely effective in the treatment of psoriasis, with 37%–40% of patients reporting a 75% improvement in their condition.”

Skin disorders that methotrexate can be used to treat include eczema, cutaneous lupus, cutaneous sarcoidosis, blistering disorders and cutaneous lymphoma. Although psoriasis is the only licensed indication in dermatology, its use in many other conditions is supported in national guidelines. It’s taken once a week as a tablet, liquid or injection; and treatment success depends on the type and severity of the patient’s condition.

Tackling myths and misconceptions surrounding methotrexate

Several misconceptions have developed around methotrexate — and amplified by social media. Chief among them is that methotrexate is chemotherapy.

“A relative of methotrexate, known as aminopterin, was first used as long ago as 1948 to treat leukemia,” says Dr King. “And methotrexate has been, and still is, used in chemotherapy. For example, dermatologists sometimes use it to treat cutaneous lymphoma, which is cancer. But with psoriasis and eczema, etc., we use it differently: our aim is to suppress the inflammatory process in the body that causes these skin conditions.”

Plus, with chemotherapy, a patient might receive very high doses of methotrexate; whereas most non-cancerous skin conditions can be treated with the lowest effective dose. While the drug has potential side effects (including nausea), hair loss should not be one of them — although hair thinning may occur in a small number of patients.

It’s our job to educate patients with scientific fact so that they can make an informed decision.

Another misconception is that methotrexate causes liver damage. “In rare cases, it can affect liver function and cause hepatitis, which is inflammation of the liver, or fibrosis, which is scarring of the liver,” says Dr King. “We monitor patients very closely so that the drug can be administered safely, usually with clinic follow-up, regular blood tests and sometimes a scan of the liver called a fibroscan. If we have any concerns, we might decrease the dose, stop prescribing it or seek advice from a hepatology specialist.” Patients taking methotrexate do not have to give up alcohol entirely (another misconception); although, they are advised against drinking excessive amounts and should certainly keep within the UK chief medical officer’s guidance, which includes not drinking more than 14 units of alcohol per week.

Contrary to some opinions voiced on the internet, methotrexate is not a drug that has to be taken for life. It’s not a cure for a skin condition either. “Patients can stop taking methotrexate and not experience any further issues,” says Dr King. “But, in most instances, it is regarded as a long-term treatment.”

Carefully weighing the risks and benefits of medication

The final myth is that female patients being treated with methotrexate cannot have children. “It does not affect long-term fertility,” explains Dr King. “However, it can cause foetal abnormalities, so it’s recommended that women taking the drug should be mindful of contraception and ideally use two effective forms of birth control while on the medication. Guidelines say that after three months of stopping methotrexate, it is then safe to conceive.” Males taking methotrexate should also use an effective form of contraception.

Don’t take your medical advice from the internet, says Dr King. See a doctor who will answer any concerns you may have surrounding a prescribed medication. “It’s our job to educate patients with scientific fact so that they can make an informed decision,” says Dr King. “Before prescribing any treatment, we will always carefully weigh its risks and benefits.”

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