Integumentary System

Structure of Skin

The skin is divided into two primary layers:

Epidermis

The outer layer of skin.

Dermis

The inner layer of skin.

Functions

• Protecting internal organs against infection, injuries and harmful chemicals.
• Maintaining body temperature.
• Synthesizing vitamin D when exposed to sunlight.

Skin lesions

• Vesicles – Small blisters with clear fluid < 10 mm.
• Bulla – Large blisters with clear fluid > 10 mm.
• Cyst – A sac-like structure filled with fluid or semisolid material.
• Fissure – A crack-like opening or slit.
• Erythema – Redness of the skin.
• Nodule – Large elevation in the skin; movable lumps.
• Papule – Small elevation in the skin; movable lumps.
• Polyp – Mushroom-like growth on a slender stalk which protrudes outwards.
• Macule – A flat discoloration of skin.
• Wheals – A swollen, discoloured area of skin.
• Pustule – Elevation containing pus.
• Ulcer – Lesion in the mucous membrane that may lead to bleeding/inflammation.

Symptoms

• Any skin lesions
• Disturbances of skin sensation
  • Anesthesia
  • Hypoesthesia
  • Paresthesia
  • Hyperesthesia
• Rashes, possibly with itchiness or pain
• Swellings, lumps or masses
• Discolored skin patches (abnormal pigmentation)
• Dry skin
• Open sores, lesions or ulcers
• Peeling skin
• Red, white or pus-filled bumps
• Scaly or rough skin

Conditions & Diseases

• Dermatitis / Eczema – Inflammation of skin due to allergy to certain foods, drugs or chemicals.
• Cellulitis – Inflammation of skin due to infection.
• Urticaria (Raised wheals) – Severe itching caused by contact with irritants or allergens.
• Alopecia – Loss of hair.
• Petechia – Small pinpoint haemorrhages.
• Wart – Thickening of epidermis due to viral infection.
• Varicella – Viral infection (chickenpox).
• Cyanosis – Bluish/purple discoloration of skin due to lack of oxygen.
• Abrasion – Removal of superficial layer of skin.
• Vitiligo – Irregular milky-white patches surrounded by normally pigmented skin.
• Xeroderma – Excessive dryness of skin.
• Tinea – Group of fungal infections (ringworm).
• Tinea pedis – Athlete's foot: itching, scaling, redness of toes.
• Tinea barbae – Fungal infection of beard area (face & neck).
• Onychomycosis – Fungal infection of nails.
• Albinism – Inability to produce melanin.
• Hematoma – Collection of blood under the skin.
• Pruritus – Itching.
• Lipoma – Benign fatty tumour.
• Herpes simplex – Viral infection due to herpes simplex virus.
• Hyperhidrosis – Excessive sweating.
• Impetigo – Bacterial skin infection causing red sores that break and ooze.
• Psoriasis – Chronic autoimmune disease affecting scalp, face, elbows, genital area, knees, buttocks.

Investigations

• Biopsy
• Laboratory tests

Skin Procedures

• Biopsy – Removal of a piece of skin to be sent to the laboratory.
• Excision – Surgical removal of abnormal growths.
• Repair – Suturing of wounds.