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Skin Conditions and Disorders

This page is divided into the following sections:

  1. Congenital Skin Condition
  2. Bacterial Skin Conditions
  3. Viral Skin Conditions
  4. Fungal Skin Conditions

 

1. Congenital Skin Conditions

Eczema

A common skin condition characterized by reddening (erythema) and vesicle formation, which may lead to weeping and crusting.
It is endogenous, or "constitutional". This means that outside agents do not play a primary role. (Contrast this with 'dermititis', in which case outside agents DO play a primary role.) However in some contexts the terms 'dermititis' and 'eczema' are used interchangeably to refer to the symptoms of these skin conditions.


There are five main types of eczema:

1.

Atopic Eczema, which is associated with asthma and hay-fever.

2.

Seborrhoeic Eczema (or Dermititis), typically affecting the scalp, eyelids, nose, and lips; associated with the presence of Pityrosporum yeasts; common among AIDS patients.

3.

Discoid (or Nummular) Eczema, characterized by coin-shaped lesions and only occuring in adults.

4.

Pompholyx, affecting only the hands and feet.

5.

Gravitational (or Stasis) Eczema, associated with poor venous circulation
(sometimes referred to as'Varicose Eczema').

Psoriasis

A chronic skin disease in which scaly pink patches form on the elbows, knees, scalp, and other parts of the body. Psorisis is one of the commonest skin diseases in Britain, affecting about 2% of the population (cause unknown).
This disorder often runs in families, the commonest time of onset being in adolesence.
It sometimes occurs in association with arthritis. Occasionally the disease may be very severe, affecting much of the skin and causing considerable disability in the patient.

While psychological stress may make psorisis worse, the only significant event thought to precipitate this condition is a preceeding streptococcal infection.

Dermatitis

An inflammatory condition of the skin caused by outside agents. (Contrast this with eczema, an endogenous disease in which outside agents do NOT play a primary role).

Primary irritant dermatitis may occur in anyone who has sufficient contact with irritants such as acids, alkalis, solvents and (especially) detergents.

Primary irritant dermatitis is the commonest cause of occupational dermatitis in hairdressers, nurses, cooks etc..

In the case of allergic contact dermatitis skin changes resembling those of eczema develop as a delayed reaction to contact with a particular allergen, which may be present at low concentrations.

The commonest example of allergic contact dermatitis in women is nickel dermatitis due to the metal nickel used in jewellery, jeans studs etc, whereas

In men chromium dermatitis is relatively common.
Treatment of dermatitis depends on removing the cause, which is not always possible.

Dermititis herpetiformis is an uncommon very itchy rash with symmetrical blistering, especially on the knees, elbows, buttocks and shoulders. It is related to sensitivity to gluten.

2. Bacterial Skin Conditions

Acne vulgaris

A common inflammatory condition of the sebaceous glands. These grease-producing glands are under androgen control, but the cause of acne is unknown. It involves the face, back and chest and is characterized by the presence of blackheads with papules, pustules - and in more severe cases - cysts and scars.
Acne is readily treatable.

Impetigo

A superficial bacterial infection of the skin.

Nonbullous impetigo is caused by Staphylococcus aureus, Streptococcus species, or both organisms. It mainly affects young children and is highly contagious, with yellowish-brown crusting.

Bullous impetigo is caused by Staphylococcus aureus. It is characterized by blisters, is less contagious than the nonbullous form, and occurs at any age.

Acne Rosacea

A chronic inflammatory disease of the face in which the skin becomes abnormally flushed. At times it may become pustular and there may be associated keratitis (inflammation of the cornea of the eye).
The disease occurs in both sexes and at all ages but is most common in women in their thirties.
The cause is unknown.

3. Viral Skin Conditions

Warts

A wart is a benign growth on the skin caused by an infection with 'human papillomavirus'.
(However, a few of the many types of this virus are known to be a causal factors in the production of tumours, which is why it is good advice to have new/unknown growths on the skin checked by a qualified person.)

Common Warts firm horny papules (1-10mm in diameter) usually located on the backs of the hands.
Most will clear spontaneously within two years.

Plantar warts (or verrucae) can occur on the soles of the feet and are often tender and especially sensitive to pressure.

Plane warts are flat, skin coloured, and therefore difficult to see.
They are usually located on the face and may be present in very large numbers.

Genital warts are frequently associated with other genital infections.
Infected women have an increased risk of developing cervical cancer.

Verrucas

Also known as 'Plantar Warts'.

Herpes

Inflammation of the skin or mucous membranes that is caused by herpes viruses and characterized by collections of small blisters.
There are two types of herpes.

Herpes simplex

There are two types of Herpes simplex (HSV):
Type I causes the common cold sore , which is usually present on or around the lips.
Type II is mainly associated with genital herpes and is sexually transmitted.
Types I and I can both cause either genital herpes or cold sores, depending on the site of initial infection. HSV blisters are contagious through skin-to-skin contact and are recurrent in some people. HSV can also affect the conjunctiva.

Herpes zoster

Also known as "Shingles", this is caused by the varicella-zoster virus, which also causes chickenpox. Following an attack of chickenpox, the virus lays dormant in the dorsal root ganglia of the spinal cord.
Later, due to one of various stimuli, the virus may migrate down the sensory nerve to affect one or more dermatones on the skin in a band, causing the characteristic singles rash. One side of the face or eye (ophthalmic zoster) may be involved. Shingles may be chronically painfully (post-herpetic neuralgia), especially in the elderly.

4. Fungal Skin Conditions

Tinea corporis, manus, pedis

Also known as "Ringworm", this is a fungal infection that can affect the skin, the scalp, or the nails.
Ringworm is caused by the dermatophyte fungi - species of Microsporum, Trichophyton, and Epidermophyton - and also affects non-human animals, which may be a source of infection for peope.
It can be spread by direct contact or via infected materials. The lesions of ringworm may be ringlike and may cause intense itching.

Tinea pedis (Athelete's Foot) is the commonest form of ringworm and affects the skin between the toes.

Tinea capitis is another common form of ringworm and affects the scalp.

Tinea cruris is the form of ringworm that affects the groin and thighs.

Tinea barbae is the form of ringworm that affects the skin under a beard.

Ringworm is often treated with anti-fungal agents, which may either be taken by mouth (orally), or applied locally.

Verrucas

Plantar Warts - see above.

Folliculitis

Inflammation of the hair follicles in the skin, commonly caused by infection.
Folliculitis may be caused by Pityrosporum yeasts.

Boils

Tender inflamed areas of skin that contain pus.
The infection is usually caused by the bacterium Staphylococcus aureus entering through a hair follicle or a break in the skin. Local injury or lowered constitutional resistance may encourage the development of boils.
These usually heal when the pus is released, or with antibiotic treatment (though occasionally the latter may cause more widespread infection).
The medical name for a "boil" is a "furuncle".

This page only includes the most common skin conditions that are included on many first-level exam courses.
Information about the structure of skin is also included on this website.

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Diagram of the structure of skin

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