Unexpected dermatological reactions to medications

Drugs can be the answer to many dermatological problems – but they can also be the cause of many skin problems. Sometimes a drug unexpectedly helps skin conditions, and sometimes a drug causes an unexpected adverse reaction.

David R. Adams, M.D., Pharm.D., is both a dermatologist and a pharmacist. An assistant professor of dermatology at Penn State's Hershey Medical Center, Dr. Adams tells Dermatology Times that there are dozens of cases of unexpected drug reactions, and he outlines a few interesting actions of drugs in dermatology.

Dr. Adams reviews a number of skin conditions and how medications affected the patients - positively or negatively.

Pityriasis rosea is a post-viral skin condition that usually occurs in children and young adults. It a harmless condition which takes from several weeks to several months to resolve. Dermatologists usually recognize it easily and it is often left untreated unless it's itchy, but the appearance can be of cosmetic concern to some.

Dr. Adams says, "We don't know a whole lot about it, but in a small placebo-controlled study about four years ago, oral erythromycin was used for two weeks and the eruption cleared in a majority of treated and in none of the placebo-treated patients.

"There is no rhyme or reason why this works since it is not a bacterial disease, but this study indicates erythromycin - and European data indicates clarithromycin - might make it go away more quickly. So, while pityriasis rosea can last several months, it could be gone in two weeks if patients use this relatively safe treatment which may work in some percentage of these patients."

Another condition, Hidradenitis suppurativa, is a debilitating, painful, scarring inflammatory condition of the body creases, and it may be treated with infliximab.

"This is a report we did at the Hershey Medical Center. We used an infusion of Remicade (Centocor) or infliximab on a patient with a very resistant case of hidradenitis suppuritiva and had significant improvement," Dr. Adams says. (Arch Dermatol 2003;139:1540-42)

Dr. Adams says the available treatments for hidradenitis suppurativa are poor. Antibiotics, anti-inflammatory medications, Accutane (Roche), and surgery are all modalities currently used in a condition that affects about one in 300 people.

"In surgery you cut out the affected areas but often the condition reccurs adjacent to the excised areas.

"We used Remicade in one patient and it put the condition into remission for about four or five months after three infusions. The patient then received periodic infusions after that. It seems to reduce the problem significantly for a reasonable length of time."

Warts are another condition that may respond to a non-standard medication regimen. Administration of oral zinc sulfate for two months may help warts disappear in some patients.

"You know what they say, when there are a whole bunch of different treatments for a condition, it usually means that not any one of them works well," says Dr. Adams.

This treatment falls into the same category. Based on a study undertaken in Iraq, use of zinc sulfate is one more method he says may help some patients. In Dr. Adams' experience, it has worked on about three out of the 20 patients who tried it. For two months, patients take 220 mg of zinc sulfate three times a day with food.

It shouldn't be used in children, but is appropriate for teenagers and adults. Neither is it indicated for patients with histories of gastrointestinal disease or stomach ulcers because it can be irritating to the stomach.

Dr. Adams says it's a simple, safe method to try for recalcitrant warts.

"These aren't huge scientific advances, but we have a lot of hard-to-treat problems, and these give us other potential treatments to try. Doctors should think beyond usual therapy or diagnoses in difficult cases."

Adverse drug reactions

Dr. Adams also addresses a number of adverse reactions - some not commonly seen - that patients can have to drugs.