practical notes on clincal dermatology for fifth year

The Skin, hair and nails,
By: Kareema Ameene Husein Al-Khafaji
M.B.Ch.B., D.V.D., MSc.
University of Babylon, College of Medicine.
Printed on Microsoft word
Introduction
The skin is the largest organ of the human body, it covers an area of approximately 2m² and weights 4kg, it is not as usually supposed merely an external covering, but a complex structure, sophisticated vital organ consisting of a number of layers and tissue component ( fig.1,2,3),with many important functions (Box.1).


Box 1 Functions of the human skins

Function Structure/cell involved
protection against;
chemical, particle horny layer
ultraviolet radiation melanocytes
antigens, haptens, microbes Langerhans cells
Preservation of a balanced internal horny layer
environment.
Prevent loss of water, electrolyte horny layer
and macromacules.
Shock absorber dermis and subcutaneous fat
Temperature regulation blood vessels + eccrine sweat glands
Insulation subcutaneous fat
Sensation specialized nerve endings
Lubrication sebaceous glands
Protection and prising nails
Calorie reserve subcutaneous fat
Vitamin D synthesis keratinicyte
Body odour/pheromones Apocrine sweat glands
Psychological display skin, lips, hair and nails


Skin is a mirror of the internal body organ, its examination reflects a lot of internal diseases, so the physician must has a good knowledge in dermatology to diagnose the common skin diseases as well as the skin manifestations of internal organs such as; thyrotoxicosis, hypothyroidism, acromegaly , Addison disease, diabetes mellitus , leprosy, ulcerative colitis, internal malignancy,..etc.with naked eye, but one should suggested that “what the mind dose not know, the eyes cannot see” .So dermatology is a visual clinical specialty. The accurate diagnosis of most skin lesions requires an adequate history, careful examination of the patient preferably in a natural light, some times magnifying lens is useful and occasionally, laboratory investigations might be needed.

The out line of an approach to dermatologic diagnosis:

1-Epidemiology and Etiology;
Age, sex, race, occupation, address.
11-History of present skin condition;
A-Duration of onset of skin lesions in: days, weeks, months, years.
B-Site of onset, details of spread.
C-Exacerbating factors like relation ship of skin lesions to; season,
heat, cold, drug ingestion, alcohol intake, occupation, hobbies, exposure to
irritants, effects of mense, and pregnancy.
D-Skin symptoms: itch, burning, pain, paresthesia.
E-Constitutional symptoms;
1-“Acute illness” syndrome: headaches, chills, fever, weakness.
2-“Chronic illness”syndrome: fatigue, weakness, anorexia, wheight loss,
malaise.
F-Past history of skin disorders
G-past general medical history inquires specifically about asthma and hay fever.
H-Family history of skin disorders; if positive-inherited, infection/infestation.
I- Family history of medical disorders.
J- Drugs used to treat present skin condition; topical, systemic, physician
Prescribed? , patient initiated?
K- Drugs prescribed for other disorders (including those taken before onset of
Skin disorder).
L-Systemic review.