Drug Eruptions and other Allergic Reactions

Drug eruptions, also known as drug rashes, occur when the body has an adverse or allergic reaction to a drug you are taking.  Because there are so many possible drugs that cause drug eruptions, there are many different types of rashes that develop. The type of rash can range from mild to life-threatening and the timing can vary from development right away to a few weeks after you first take the medicine. In terms of appearance, drug eruptions can appear as  pink or red bumps, hives, blisters, red patches, pus-filled bumps (pustules), or sensitivity to sunlight. Drug rashes can impact the entire skin surface, or they may be limited to one or a few body parts. Itching is a common symptom in many drug rashes. Allergic reactions can be serious and even fatal. If a rash develops, it is important to see a dermatologist right away to seek treatment.


Contact Dermatitis/Patch Testing

Contact dermatitis is a common form of skin inflammation that creates a red, itchy, non-contagious rash.  It is caused by direct contact with a substance or an allergic reaction to it. Symptoms of contact dermatitis include:


  • Red, irritated skin
  • Itching
  • Swelling
  • Bumps or blisters, sometimes filled with clear fluid
  • Hot or tender skin


Symptoms can comes as early as a few hours after contact to 10 days after contact with the irritant or allergen.  You can even develop an allergy after using something for years.


To treat contact dermatitis, first we treat the irritated skin by prescribing either a cream, an oral medication, antihistamines, or ointments to relieve the itching and help restore the damaged skin. It is important to avoid scratching the affected area to prevent infection.


The next step is for us to determine what caused the reaction so you can avoid that allergen or irritant in the future. Some common irritants that cause dermatitis include:


  • Solvents
  • Rubbing alcohol
  • Bleach and detergents
  • Shampoos, permanent wave solutions
  • Airborne substances, such as sawdust or wool dust
  • Plants such as poison ivy, poison oak, and poison sumac
  • Fertilizers and pesticides
  • Nail polish
  • Metals like new jewelry or watches
  • Clothing dye or hair dye


To test for a skin allergy, we use what is called a patch test. Patch testing is done by applying tiny amounts of up to 25 or more substances as small patches to your skin fixed on with non-allergic tape. After two days with the patches on, we remove the patches and examine the skin to check for reactions to any of the tested substances. The same process is done two days after that to check for any delayed reactions to the substances.



Psoriasis is a common skin condition that speeds up the life cycle of skin cells. This causes cells to build up rapidly on the surface of the skin forming itchy and sometimes painful scales and red patches. Psoriasis is a chronic disease that often comes and goes, but is not contagious. Common locations for psoriasis to develop are the scalp, face, hands, feet, nails, genitals, and any skin folds such as armpits and under the breasts. There are five main types of psoriasis:


  • Plaque psoriasis, the most common form of the disease, appears as raised, red patches covered with a silvery white buildup of dead skin cells. These patches mainly develop on the scalp, knees, elbows and lower back, are often itchy and painful, and can crack and bleed.
  • Guttate psoriasis, the second-most common type of psoriasis, is a form of psoriasis that appears as small, dot-like lesions. It often starts in childhood or young adulthood, and can be triggered by a strep infection.
  • Inverse psoriasis shows up as very red lesions in body folds, such as behind the knee, under the arm, under the breast, or in the groin. It may appear smooth and shiny. Many people with inverse psoriasis tend to have another type of psoriasis elsewhere on the body at the same time
  • Pustular psoriasis is characterized by white pustules (blisters of noninfectious pus) surrounded by red skin. Pustular psoriasis can occur anywhere on the body, but occurs most often on the hands or feet.
  • Erythrodermic psoriasis, the rarest form of the disease, is particularly severe as it leads to widespread, fiery redness over most of the body. It can cause intense itching and pain, and can cause the skin to come off in sheets.


Some people who have psoriasis develop a form of arthritis called psoriatic arthritis. Most cases of psoriatic arthritis are diagnosed after the diagnosis of psoriasis, but the joint problems can sometimes begin before skin lesions appear. Common symptoms of psoriatic arthritis are swollen fingers and toes, foot pain, and lower back pain.


The main goal of treatment is to stop the skin cells from growing so quickly. Treatment for psoriasis and psoriatic arthritis can be provided in the form of systemics, also known as biologics. Biologics are different from traditional systemic drugs because they target specific parts of the immune system. The biologics used to treat psoriatic disease block the action of immune cells and proteins that cause psoriasis and psoriatic arthritis.



Eczema, also known as atopic dermatitis, is a chronic, non-contagious, inflammatory skin condition characterized by severe itching, redness, oozing, and scaly rashes. Eczema causes extremely dry and sensitive skin and can be made worse if it is exposed to substances such as allergens, soaps, detergents, lotions with heavy fragrances, perfumes, and cleaning products. For some, changes in weather worsen their eczema. Most people with eczema begin experiencing symptoms as children by at least age 5. The condition is hereditary so those born into a family that have a history of allergic diseases such as asthma or hay fever are at an increased risk for developing eczema.


While most children outgrow the condition, adult eczema can be a serious condition. For adults, eczema can cause unbearable itching and flare-ups that affect skin all over the body. The rashes or red patches are typically found inside the folds of the elbow and knees and the dry skin can crack and bleed. Treatments include over-the-counter products, prescription topical creams, phototherapy, systemic medications, biologics depending on the severity of the eczema.



Vitiligo is a condition that causes the loss of skin color in blotches. The rate and intensity of color loss from vitiligo is unpredictable and it can affect the skin or any part of your body including your hair and the inside of your mouth. Melanin is what gives your skin and hair their natural color. Vitiligo occurs when the cells that produce melanin die or stop functioning. The condition is not life-threatening or contagious. Vitiligo can start at any age, but often appears before age 20.


There are three main types of vitiligo which are based on how much of your body is covered with discolored patches:

  • Generalized Vitiligo: This is the most common type and is categorized by discolored patches on many parts of your body. The discolored patches often progress similarly on corresponding body parts (symmetrically).
  • Segmental Vitiligo: This type is categorized by discolored patches covering only one side or part of your body. It tends to occur at a younger age, progress for a year or two, then stop.
  • Focal Vitiligo: This type is categorized by discolored patches on one or only a few areas of your body


The discolored patches sometimes stop forming without treatment. However, often times pigment loss spreads and eventually involves most of your skin. Treatment for vitiligo may restore color to the affected skin, but does not prevent continued loss of skin color or a recurrence.