Disorders of Skin

Learning Outcomes

  • Describe several different disorders of the skin

Two common skin disorders are eczema and acne. Eczema is an inflammatory condition and occurs in individuals of all ages. Acne involves the clogging of pores, which can lead to infection and inflammation, and is often seen in adolescents. Other disorders, not discussed here, include seborrheic dermatitis (on the scalp), psoriasis, cold sores, impetigo, scabies, hives, and warts.

Eczema

This photo shows a person with eczema on the ventral skin of the forearms. The person is a Caucasian, but his or her white skin is mottled with many red marks, giving it the appearance of a rash. In some areas, the skin is breaking and peeling.

Figure 1. Eczema is a common skin disorder that presents as a red, flaky rash. (credit: “Jambula”/Wikimedia Commons)

Eczema is an allergic reaction that manifests as dry, itchy patches of skin that resemble rashes (Figure 1). It may be accompanied by swelling of the skin, flaking, and in severe cases, bleeding. Many who suffer from eczema have antibodies against dust mites in their blood, but the link between eczema and allergy to dust mites has not been proven. Symptoms are usually managed with moisturizers, corticosteroid creams, and immunosuppressants.

Acne

Acne is a skin disturbance that typically occurs on areas of the skin that are rich in sebaceous glands (face and back). It is most common along with the onset of puberty due to associated hormonal changes, but can also occur in infants and continue into adulthood. Hormones, such as androgens, stimulate the release of sebum. An overproduction and accumulation of sebum along with keratin can block hair follicles. This plug is initially white. The sebum, when oxidized by exposure to air, turns black. Acne results from infection by acne-causing bacteria (Propionibacterium and Staphylococcus), which can lead to redness and potential scarring due to the natural wound healing process (Figure 2).

Three diagrams show the progression of acne in three steps from left to right. All three depict a cross section of skin containing a hair follicle. In the left diagram, the follicle has a swollen area about halfway up the hair shaft, just above a sebaceous gland. The follicle is plugged with sebum, depicted as a yellowish substance. In the middle diagram, the follicle has become more swollen, as a label indicates that bacteria are reproducing within the blockage. The surrounding epidermis becomes inflamed as a result of the bacterial infection. In the rightmost image, the blockage has swollen to about five times its original size and has broken the surrounding epidermis, which is now red and inflamed.

Figure 2. Acne is a result of over-productive sebaceous glands, which leads to formation of blackheads and inflammation of the skin.

Practice Question

Why do teenagers often experience acne?

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