Diseases of Skin

Inflammatory Diseases:

Acne

Acne is a chronic inflammatory disease of the sebaceous (oil) glands and hair follicles.  The scattered lesions caused by acne can manifest as single or multiple bumps generally called nodules or papules.  The lesions are associated primarily with the sebum-producing glands that surround hair follicles in skin that is visibly greasy. Lesions are typically distributed to the face, neck, chest, shoulders, back and upper arms.

Dermatitis /Eczema

Both dermatitis and eczema refer to superficial inflammatory diseases of the skin.

Contact Dermatitis (CD)

Contact dermatitis is an inflammation caused when your skin comes in contact chemical allergens or mechanical irritants.

Primary-irritant CD is a nonallergic skin reaction to an irritant.  Lengthened or repeated exposure to the irritant is necessary to cause skin damage.

Allergic CD is a delayed hypersensitivity dermatitis. This a cell-mediated hypersensitivity reaction to allergens in the environment.  Some causes of allergic CD include:  poison ivy, industrial chemicals, various drugs, latex, hair dyes, and some metals.

Atopic Dermatitis

Atopic dermatitis occurs in people who have a lower natural threshold to resist itching.  The threshold to resist itching is genetically determined.  One factor in this disease may be a dysfunction in the immune system.

Atopic dermatitis usually begins in childhood.  It is common in the Western World and is associated with a family history of asthma or hay-fever.

Lesions are produced primarily by scratching.  With intense scratching, the lesions develop redness, weeping, and scaling.  Lesions most often occur on the neck, behind the knee, and the inside of the arm at the elbow.  Factors that exacerbate (worsen) the dermatitis include:  sudden changes in weather, stress, wool, furs, and irritant chemicals.

Individuals who suffer from atopic dermatitis must avoid factors that cause or exacerbate the condition.  Treatment usually involves topical agents such as corticosteroids , anti-infectives , or UV therapy.

Seborrheic Dermatitis (SD)

This disease is seen most often in areas of the body that have many sebaceous (oil) glands, such as the scalp and eyebrows.  It appears as an accelerated, immature epidermal (outer skin layer) growth.  Its noninflammatory counterpart is dandruff .

SD is one of the skin signs associated with HIV infection.  Infantile SD (diaper rash) usually occurs within the first three months after birth.  Infantile SD does not appear to cause itching.  The infantile SD lesions are responsive to topical corticosteroids. Some ointments include an antifungal agent as well to prevent a candidal (fungal) infection.

Fungi appear to play a role in the inflammation of SD. SD is treated by using special shampoos and topical corticosteroids or antifungal agents.

Psoriasis

Psoriasis is a common, chronic, genetically determined dermatitis.  It consists of pink or dull-red elevated lesions that have a characteristic silvery scale.  Lesions may be small individual points or large fused patches.  The classical locations for lesions are the scalp, knees, elbows, umbilicus (belly button), and the sacral area--the area at the base of the spine, between the hipbones.  Psoriasis may be accompanied by joint pain.

Psoriasis may be, at least in part, an autoimmune disorder (where the immune system falsely recognizes portions of the body as "foreign").  Risk factors that indicate a higher chance of acquiring psoriasis include:  stress, infections, certain medications, immunologic factors ( HIV ), and family history.  There is some association with arthritis.

Topical treatment is preferred when less than 20% of the body involved.  Medications used to treat the condition include corticosteroids, topical coal tar, salicylic acid, Vitamin D derivatives, etretinate, methotrexate, and cyclosporine.
 

Viral Infections

Herpes Simplex

The lesions produced by the herpes simplex virus are commonly known as the cold sore or fever blister. They are caused by herpes simplex type 1 virus.  The virus cannot be eliminated once it is acquired. It continues to be present in nervous tissue throughout your life.

The herpes-simplex lesions may appear anywhere on the body.  Most often, they are seen on the lips, oral and genital areas. Eruptions may be caused by stress, fever, sun exposure, common cold or injury.

Active lesions are infectious to the patient and to others. Recurrent lesions are often preceded by a tingling sensation in the area. Lesions usually clear in 7-10 days. Currently, there is no cure for herpes simplex type 1.  Treatment is directed at symptomatic relief.  Antiviral agents can shorten attacks by decreasing viral replication.
 

Chicken Pox (Varicella)

This disease is caused by the herpes zoster virus.  Chicken pox is a highly contagious, airborne virus. It affects children much more often than adults. The incubation period is 10-20 days. General symptoms include fever, headache, anorexia, malaise, and lesions.  The lesions appear as small, pink, raised spots surrounded by a reddened halo.

Treatment includes keeping the lesions dry, and relieving the itching to prevent people from breaking the lesions open and spreading the virus.

Usually the lesions cause no significant scarring.  Sometimes a small pock-mark may be left after the lesion has healed.

Herpes Zoster

This is often referred to as shingles and occurs most often in the elderly . This acute disease occurs when the dormant virus (Varicella) becomes active.  The active virus produces intense itching, pain and grouped vesicles along a unilateral dermatome (generalized area associated with a specific nerve). The virus remains dormant along nerve tracts, and is thought to migrate to the surface when activated. The vesicles usually crust and clear in about 2-3 weeks. Several antiviral drugs such may be used to shorten the duration of the infection

Warts

Warts are raised, well-defined growths with an irregular gray surface.  The warts seen on the hands are called verruca vulgaris or the common wart. The human wart virus is transmitted by direct contact, but may be autoinnoculated by razors in shaving , for example. Warts almost always regress spontaneously but sometimes they are removed by freezing, by the use of topical salicylic acid, or OTC wart removal treatments.

Verruca plantaris tends to grow on the soles of the feet.  Warts on the feet are painful because of the irritation of walking. These warts tend to grow inwardly.

Condylomata acuminata are large, pink or purple lesions located primarily in warm moist anal or genital areas. Although commonly known at venereal warts, they do not necessarily arise from sexual contact.

Rubeola (Measles)

This disease usually begins with fever, malaise and the symptoms of a cold.  This stage lasts about 24 hours.  This initial stage is followed by a second stage, which lasts 4-7 days, and which causes fever, chills, headache, photophobia, and dry cough.  The measles lesions begin as small bumps on the rear of the roof of the mouth or (classically) behind the ears on about the 3rd to 7th day.  Spots then appear on the face, arms and torso. The virus is spread by direct contact with secretions of the nose and throat of an infected person. Treatment is symptomatic. Vaccination is available for prevention and is normally required for school attendance.

Rubella (German Measles)

Rubella is a highly contagious viral disease transmitted by contact with nasal or oral secretions of an infected person.  It causes a mild fever and malaise (feeling of bodily discomfort) about 4-5 days before lesions appear.  The lesions manifest as small, irregular, pink spots or bumps that usually appear on the face before spreading to the entire body. These lesions fade within 2-3 days.

Vaccination is very effective and is usually given to children at the same time as the rubeola vaccine. Vaccination of post-pubertal women is avoided if pregnancy is confirmed or suspected. Pregnancy should be avoided within the first 3 months after vaccination.

Rubella is especially dangerous in pregnant women.  The virus can cross the placental barrier and infect the fetus, resulting in severe birth defects.
 

Bacterial Infections

Impetigo

This acute bacterial infection occurs on the surface of the skin.  It manifests first as vesicles that contain a light, yellow fluid.  The vesicles rupture and form a golden crust.

Impetigo usually occurs in children.  The infection can be transmitted between humans.  The infection can also be transmitted from one site to another on the same person. Causes of impetigo include streptococci and the staphylococci bacteria.  Poor hygiene, tropical climates, and improper sanitation can contribute to infections. Topical treatment may resolve mild infections, but most cases require oral antibiotics to resolve.

Folliculitis

Staphlococci are usually the culprit of this bacterial infection of hair follicles . The basic lesion is a red spot or bump surrounding the hair follicle.  Poor hygiene can contribute to folliculitis. If not treated properly, with appropriate antibiotics, the infection can extend into deeper skin layers.

Furuncle & Carbuncle

Boils (furuncle) usually develop from an infected follicle. Irritation and poor hygiene can contribute to boil development. Usually these lesions appear as a small reddish bump that is tender.

A carbuncle is a larger staphylococcal abscess that drains from the furuncle lesion. These occur most often in the elderly , the ill, or in diabetics.  Systemic antibiotic therapy is usually necessary to cure carbuncles.
 

Fungal Diseases

Common superficial fungal diseases of the skin include ringworm, athlete's foot, and jock itch.  Moisture and heat are contributing factors to these infections.

Common fungal diseases invade the superficial layers of the epidermis, hair, and nails .  They cause scaling, redness, itching, fissures, and vesicles.  Treatment usually involves local therapy with antifungals.