S'pore man hospitalised 10 days following skin rash treatment, doctor suspended from practice for 14 months

A man, who visited Naaman Skin and Laser Centre in Novena to treat rashes on his body, was hospitalised for 10 days with bone marrow suppression after his dermatologist changed the medication prescription.

According to the Singapore Medical Council (SMC) disciplinary tribunal's grounds of decision, the centre's consultant dermatologist Khoo Boo Peng pleaded guilty to two charges of professional misconduct under the Medical Registration Act 1997.

Khoo has since been suspended from practice for 14 months.

Initial treatment

The patient first visited the centre on Apr. 13, 2020 to consult Khoo for rashes on his body, which he had been suffering from since August 2019.

Khoo diagnosed him with prurigo nodules, a skin condition that causes itchy bumps on the skin.

The doctor also gave the patient a steroid injection.

On Apr. 27, 2020, Khoo prescribed the patient with Cyclosporin and Methotrexate.

Cyclosporin is an immunosuppresive agent and Methotrexate is a chemotherapy agent and immune-system suppressant.

Since the patient felt well on May 15, 2020 and the drugs were expensive to continue in the long term, they were stopped.

Change of medication

The patient relapsed on Jun. 12, 2020 and consulted Khoo again.

This time, Khoo changed the medication and prescribed the patient with Azathioprine and Prednisolone.

Azathioprine is an immuosuppressive medication.

Prednisolone is a medication that can be used to treat skin problems.

On Jun. 27, 2020, the patient emailed Khoo with two photos of the lower part of his face, expressing concern that his face below the lips were a little swollen and his skin colour had turned darker than normal.

Khoo replied him on the same day that this appeared to be temporary fluid retention from the medication Prednisolone and to continue with the medication.

The patient emailed Khoo a few days later on Jul. 1, 2020, stating that "the steroid has caused blisters near my lips and mouth sores and probably affecting the tongue and throat as well".

"It feels painful when I eat and swallow. The darkening of skin is also quite bad," the patient wrote.

On Jul. 2, 2020, the patient followed up with more emails where he attached a photo of his hair loss and said: “This is the amount of hair I lost this morning. Never happened before. Pls advise what to do with the steroid. It is killing me. I want to stop but scare of the withdrawal symptoms also.”

Khoo agreed and told him to stop taking Prednisolone.

Serious diagnosis

On Jul. 2, 2020, after consulting Khoo via email, the patient consulted Khoo in-person on an urgent basis.

It was only then that Khoo told him the symptoms could be an adverse drug reaction to Azathioprine.

He subsequently sought treatment at Mount Elizabeth Novena Hospital's Accident and Emergency (A&E) department on Jul. 4, 2020, where he was diagnosed with bone marrow suppression and resulting pancytopenia.

Bone marrow suppression is a condition where the bone marrow does not produce enough blood cells or platelets.

The tribunal document stated that pancytopenia is potentially life-threatening.

This caused him to be hospitalised from Jul. 4 to Jul. 13, 2020.

Reasons for charges

Khoo's first charge was prescribing Azathioprine to the patient without ensuring the patient’s safety.

His second charge was failure to carry out close monitoring of the patient and proper management of the patient’s side effects after starting the patient on Azathioprine.

The tribunal document stated that Khoo should have tested the patient to see if he was a normal, intermediate, or poor metaboliser of Azathioprine.

If the patient chose not to undergo either test, Khoo should have been cautious to start the patient at the lowest dosage of Azathioprine to test how susceptible the patient was to Azathioprine.

Khoo did not take both precautions, which resulted in the patient being hospitalised as there could be serious side effects if a high dose of Azathioprine is prescribed to a patient, who is a poor metaboliser of Azathioprine.

Test results dated Jul. 9, 2020 determined that the patient was a poor metaboliser of Azathioprine.

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