Factors that predispose an individual to developing a drug rash include:
- Weakened immune system due to underlying illness or medication
- Underlying infection
- Taking more than 3 medicines daily
- Antibiotics, such as penicillin or sulfa drugs
- Anti-inflammatory medicines, such as ibuprofen, naproxen, or indomethacin
- Painkillers, such as codeine or morphine
- Seizure medications (anti-convulsants), such as phenytoin or carbamazepine
- Chemotherapy agents
- Medicines for psychiatric illnesses (psychotropic medications)
- Iodine, especially that found in X-ray contrast dye
Itching is common in many drug rashes. However, if fever is present, the skin is tender, or the membranes inside the mouth or the genitalia are involved, then a more serious skin condition may be present.
For a mild or limited drug rash, you may try the following measures:
- Take cool showers or apply cool compresses.
- Apply calamine lotion.
- Take an antihistamine, such as diphenhydramine.
Prepare a list of all of your medications, including prescription and over-the-counter pills as well as topical creams, vitamins, and herbal or homeopathic remedies for the doctor. Be sure to include medicines that you may take only on occasion. If possible, try to document when you started taking each medication. Also make certain that you know about any previous reactions you might have had to medicines or food.
- Numbing the skin with an injectable anesthetic.
- Sampling a small piece of skin by using a flexible razor blade, a scalpel, or a tiny cookie cutter (called a "punch biopsy"). If a punch biopsy is taken, a suture or two may be placed and will need to be removed 6–14 days later.
- Having the skin sample examined under the microscope by a specially trained physician (dermatopathologist).
The best treatment for a drug rash is to stop the medication that is causing it. After discontinuing a medicine, it may take 5–10 days to see an improvement in the skin and up to 3 weeks for the rash to resolve completely.
Note: Stopping a prescription medication should be done only with a doctor's guidance.
Other treatments that may be helpful include:
- Oral antihistamine pills, such as diphenhydramine, hydroxyzine, loratadine, cetirizine, fexofenadine, or desloratadine, for itching.
- Topical corticosteroid (cortisone) creams or lotions for red, inflamed skin.
- Topical antibiotic ointments for open sores.