Dermatology Basic Discussion

Dermatology: Basic Discussion

Skin is the largest organ of the body ( 8% of total body mass)

SKIN is the heaviest organ of the body (16% of total body weight )

 SKIN is the first step to your beauty !

Integumentary system  :  Skin & its appendages (hairs , nails ,sebaceous gland, sweat glands) 

Layers of the skin :


 1.Stratum corneum (Horny layer)

 2. Stratum lucidum (present in palm & sole only )

 3. Stratum granulosum

 4.Stratum spinolosum (Thickest layer)

 5.Stratum basalis / germinativum


   1. Papilary layer

   2. Reticular layer


  Thick skin means thick stratum corneum

  Thickest epidermis in palm & sole.

  Thickest dermis on the back .

  Thinnest dermis is eyelids.

Major functions of  SKIN :

Organ of protection ( Trauma , Sunlight etc.)

Secretion & excretion of substances (sweat , sebum ,drugs, etc)

Regulation of body temperature

Synthesis of Vitamin –D,

Percutaneous absorption of substance drugs)

Skin health depends on :

1. Genetic factors

2. Age

3. Environmental (occupational, sunlight)

4. Plenty of water intake

5. Anxiety free states – proper sleep – (physical & mental rest )

6. Low fatty diet & more vegetables intake

7. Avoid alcohol, tea , coffee

8. Appropiate skin care : Protection from sunlight, water wash , cosmetic use

Most common Skin problems in Bangladesh

Superficial fungal infection.

Bacterial infection

Viral infections



Eczema/Chronic Dermatitis

Atopic Dermatitis


Insect bite hypersensitivity

Seborrhoeic Dermatitis


Pigmentary disoders

Hairs & nail disorders

Nevus and skin tumours

Cutaneous symtoms : (Patients complaints )

Pruritus / Itching : may be defined as  a sensation that produce desire to scratch.

Alteration of skin color : Hyper/hypo pigmentations , reddish , yellowish

Pain & burning

Dryness & scaling

Skin rashes


Disfiguration ( Skin ,nail , mucosa )

Hairs : decrease / increase

Cutaneous signs ( Doctors findings )  Basic skin lesions

Primary lesions

Macule (< .5 cm ) Alteration of color of skin without elevation or depression 

Patch ( > .5 cm ) Alteration of color of skin without elevation or depression

Papules ( < ,5cm ) Solid epidermal elevation

Plaque (> .5cm )       Solid epidermal elevation

Nodules :         Solid epidermal & dermal elevation

Blister : Fluid containing with in epidermis or sub epidermis

Vesicles ( < .5cm )

                                                                          Bulla ( > . 5 cm)

# Secondary skin lesions:

Scales / Squama / Exfoliate / Pityriasis  :  dead keratinocytes

Crust : Dead keratinocytes +  Serum  +  Inflammatory infiltrates

Fissure : Linear crake.

Erosion : Loss of Epidermis

Ulcer : Loss of epidermis and dermis or other part.

Pustule : Pus containing cavity.

Excessive formation of connective tissue—– Collagen fibers are arranged in parallel Scar—– Collagen fibers are arranged in claw-like — Keloid

◄ Special skin lesions

Erythema : Redness of skin due to cutaneous vasodilatation ( Temporary )

Telangiectasia :  Permanent vasodilatation

Purpura : Extravasetion of blood ( Non- blanching )

Causes of generalized pruritus / itching?

Endocrine : Diabetes mellitus, Thyroid disorders-(Hyper & Hypo)

Hematological: Iron deficiency anemia,     Polycythemia,   leukemia,  lymphoma,       multiple myeloma

Enteric: Intestinal worm infestations

Hepatic: CLD, Viral Hepatitis

Renal cause: CRF

Psychological : Anxiety with depression

Physiological : Pregnancy

Dermatological ; SD, AD,scabies etc

Q common causes of generalized pigmentation?

1.Addison’s disease

2.Kala azar

3. Malaria

4.Chronic Liver disease

5.Internal Malignancy


7.Ashy Dermatosis

8.Chronic Arsenicosis

9.Drugs; Amiodaron,Busulphen,Chloroquin, Chlorpromazin,Psoralen

 Common bullous skin diseases?

1.Bullous Impetigo

2.Pemphigus vulgaris

3.Steven Johnson’s Syndrome ( Bullous drug reaction)

4.Dermatitis Herpetiformis

5.Bullous Pemphigoid

6.Insect bite Hypersensitivity

7.Herpes zoster

.Q.Common causes of oral ulcer?

1. Trauma

2.Aphthous ulcer

3.Oral Lichen Planus

4.Oral candidiasis


6.Pemphigus vulgaris

7.Secondary syphilis

8.Squamous Cell Carcinoma


10.Nutritional deficiency(Iron,Folic acid,zinc,Vit-B2)

Q.Emergency Skin diseases?

Drug reaction

Exfoliative Dermatitis

Psoriasis with arthritis

Pemphigus vulgaris


Herpes Zoster




Lepra reaction