All medications can cause a rash, but the most common ones are antibiotics, antiepileptic drugs, and anti-inflammatory drugs. The rash can appear minutes after ingestion, but more commonly, it takes days or a couple of weeks. A drug rash can also occur after prolonged use of a medication. The risk of a drug rash is higher if a person has an infection, such as mononucleosis.
This is the most common type of drug rash and is known by several names, including morbilliform or exanthematous drug rash. It typically starts 1-2 weeks after a person starts taking a new medicine, such as penicillin. The rash consists of small pink spots ranging from millimeters to a few centimeters in size, which can be slightly raised and flaky. Such spots gradually appear all over the body, sometimes starting at the upper body before spreading downwards and outwards to the arms and legs. It can be itchy. The treatment, in addition to discontinuing the medication, includes moisturizing creams, corticosteroid creams, sometimes steroid tablets, and antihistamines.
Medicines can sometimes cause hives (urticaria). In such cases, the rash typically starts minutes or hours after ingestion. Urticaria caused by medicines usually appears when the medicines are administered as injections but can also occur with tablets. This type of rash presents as itchy red wheals that last for a couple of hours before disappearing, leaving the skin looking normal afterward. The skin is smooth, without any flaking. In such cases, antihistamines are usually used to alleviate the rash and itch. In very rare cases, the patients may have breathing difficulties. In such instances, the patient should seek medical attention at an emergency department.
In rare cases, a medicine can cause a severe rash, which may require hospitalization. The typical signs include fluid-filled blisters on the skin and mucous membranes (mouth, lips, eyes), and the top layer of skin detaching from the underlying layers. Some patients report that such rashes start with pain in the skin. It is most common for antiepileptic drugs, antibiotics, and anti-inflammatory drugs to cause these severe reactions.
The answer is yes, but it is likely very rare. Itch can have many causes, one of them medicines.
