Skin Pathologies: Inflammatory & Allergic Eruptions

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  • 0:02 External vs. Internal
  • 1:15 Erythema, Pruritis, Urticaria
  • 1:54 Outside Irritants
  • 4:19 Atopic Dermatits
  • 5:45 Genetic Skin Disorders
  • 9:09 Lesson Summary
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Lesson Transcript
Instructor: Rachel Torrens

Rachel is a Nurse Practitioner with experience working as a high school teacher, skin surgery center, and as a family NP.

In this lesson, discover terms used to classify inflammatory skin conditions and their symptoms, including pruritus, erythema, psoriasis, dermatitis, erythema multiforme, urticaria, scleroderma, and ichthyosis.

External vs. Internal Stimuli for Skin Conditions

With spring comes many beautiful things - flowers budding, trees blooming, bunnies hopping. But, for many people, this time of year also comes with sneezing, watery and itchy eyes, and a runny nose. The pollen in the air acts as an irritant to the nasal passageways, causing the body to respond as if under attack. What people don't realize is that their skin can react in a very similar manner. Skin can show irritation to various external stimuli: heat, medicines, metals, and more can all trigger reactions! When the body's inflammatory response is triggered, it leads to multiple symptoms evident on the surface of the skin.

In other instances, the skin isn't irritated by external forces, but rather by internal factors. Namely, some people are born with genetic skin conditions that lead to patches of irregular skin. Depending on which gene is affected, a person can have skin that is hard like a tortoise shell or scaly like that of a fish. Such is the fascinating world of dermatology, so let's take a closer look at each one of these skin disorders.

Erythema, Pruritis, Urticaria

But before we delve into these various inflammatory skin conditions, let's review some important terms used to describe different symptoms. First, erythema is the term used to describe redness on the skin. So, the term erythematous is used often when describing rashes, which you'll see in this lesson. The term pruritus means itching sensation on the skin, and pruritic is the adjective form (i.e., 'itchy'). Lastly, remember that the term urticaria means skin welts or hives. So, you may see this term used to describe symptoms of several different skin conditions as well.

Erythema Multiforme, Cholinergic Urticaria, Contact Dermatitis

So, we'll begin with conditions that are triggered by an outside irritant of one sort or another. Erythema multiforme (EM) is an itchy skin rash produced in response to an infection or, less commonly, a medication. The rash consists of erythematous target-like lesions. The lesions usually have many different shapes and sizes, hence the 'multi-form' bit of the condition's name.

Most frequently, patients erupt in erythema multiforme following an infection, such as with the herpes simplex virus. However, it has been noted rarely after patients take certain medications, like penicillin, sulfonamides, or barbiturates. In addition to the rash, patients also experience fever and joint aches. The rash usually resolves on its own after several weeks.

Cholinergic urticaria is a skin disorder in which a person develops an itchy rash in response to heat. Some people refer to it as 'heat bumps.' Either way, it is a most unpleasant event for the person experiencing it. Usually, just before an attack, the person will feel a tingling or stinging sensation all over the skin. Then she will erupt in hundreds of small, red bumps that are extremely pruritic. The attack can last from 30 minutes to hours before spontaneously resolving.

A handy way to remember this condition is with the phrase, 'See You have Heat Hives.' The 'See' stands for the 'C' in 'cholinergic,' the 'You' for the 'U' in 'urticaria,' 'heat' is the trigger, and 'hives' is the result!

Contact dermatitis is an inflammatory skin condition in which a patient develops an erythematous, pruritic rash in response to an irritant or allergen. In this type of dermatitis, the skin senses a threat and responds with its army of white blood cells, which, in turn, triggers an inflammatory response. In some cases, the threat is an irritant, such as the chemicals in laundry detergent or urine in a wet diaper that is left on too long. In other cases, the threat is an allergen, such as poison ivy or the type of metal found in a necklace. Either way the body's immune system is attempting to waylay the perceived enemy.

Atopic Dermatitis

Now, we are going to explore another type of dermatitis, but this is dictated by one's genetic makeup. Atopic dermatitis, or eczema, is an allergic skin condition that causes the formation of rough patches of skin that are very pruritic. Usually atopic dermatitis begins in infanthood and lasts a lifetime, with the patient experiencing periodic flare-ups. Areas where the skin creases are most often affected; therefore, the elbow folds, ankle folds, and wrists are common areas. The areas affected are extremely rough, feeling like sandpaper, and cause incredible itching for the patient.

Unfortunately, this often leads to scratching that can lead to infection if not treated quickly. It is also important to note that this condition often goes along with other allergic maladies in the body, such as seasonal allergies and asthma. Where you find one, you are likely to find another.

It is important to note the difference between contact dermatitis and atopic dermatitis. In contact dermatitis, there is an outside stimulus for the inflammatory response noted on the surface of the skin. In atopic dermatitis, there is an internal stimulus (i.e., the person is just prone to allergies) for the allergic response noted on the skin.

Ichthyosis Vulgaris, Scleroderma, Psoriasis, Seborrheic Dermatitis

The next three conditions we are going to examine are genetic skin disorders in which the structure of the skin or the skin's life cycle is affected. Ichthyosis vulgaris is a genetic skin condition in which a person's skin is extremely rough and flaky. This disorder is commonly referred to as 'fish skin disease.' Sometimes, mild cases of ichthyosis vulgaris are missed and thought to be simply extremely dry skin. There is no known cure, and treatment is targeted at managing symptoms.

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