The skin is one of the essential organs of the human body and constitutes one of the five sensory organs. The skin together with its accessory organs- hair, nails and glands- form the integumentary system of the body.

Functions of the skin:

1. It serves as a protective membrane over the entire body, guarding the underlying tissues from damage due to external forces.

2. The glands present in the skin- sebaceous and sweat glands-aid in controlling the oil-water balance in the body and in thermo-regulation.

3. The nerve cells in the skin help in detecting the sensation of touch, pain or heat.

Anatomy:

The human skin is made of 3 layers:

Epidermis- This is the outermost thin, cellular, membranous layer. The protein, keratin and the black pigment, melanin are secreted from the cells of the epidermis.

Dermis/Corium- This is the middle connective tissue layer underneath the epidermis. The sebaceous glands (producing sebum) and the sweat glands have their origin in this layer.

Subcutaneous layer- This is the innermost layer which has the fat cells called lipocytes.

Skin Lesions

Any area of damaged tissue, caused by disease or external impact is known as skin lesion. Some of the skin lesions commonly noticed include:

• Cyst: A thick-walled closed sac containing fluid/semi-solid material. It is also known as a boil or a blister.
• Fissure: A crack –like sore on the surface of the skin, as in a cut.
• Macule: A discoloured flat lesion, often reddish in color, as in tattoo marks. Echymosis is the bluish-black mark on the skin caused by haemorrhages into the skin.
• Papule: This is a small, solid elevation of the skin. Pimple is a good example of a papule. Papules containing pus are referred to as pustules.
• Polyp: This is a mushroom-like growth from the skin, found commonly in nostrils.
• Ulcer: An open sore due to erosion of the top layer of the skin
• Wheal: A slightly reddish elevated area as in case of a mosquito bite.
• Wart: This is an epidermal growth caused by a virus.

Common Skin Diseases and their treatment:

Leukoderma: It is the loss of pigmentation in certain areas of the skin due to decrease/absence of melanin production. It can be treated, though not completely cured, by application of certain oils like mustard oil.

Acne: The condition of papular eruption of the skin, usually blackish in colour, is known as acne. This is formed due to accumulation of sebum and keratin in the pores of the skin. It is commonly treated with topical medicines or oral antibiotics.

Eczema/Dermatitis: Here, the skin gets inflamed, and appears reddish in colour. It is mainly caused due to an allergic reaction, though heredity is also a risk factor.  Steroid creams and moisturisers are used to control eczema, though complete cure is not easy.

Cellulitis: It is the inflammation of the connective tissue of the dermal and the and subcutaneous layers of the skin. It is usually treated with antibiotics.

Gangrene: Death of a skin tissue caused by lack of blood supply. The skin becomes black and numb. Two types of gangrene are recognised based on the source of infection; they are dry gangrene and wet gangrene. Major risk factors are untreated wounds and trauma. Oozing may occur in case of wet gangrene which is usually developed from open wounds. Treatment of gangrene is by revascularisation, administration of antibiotics or surgical debridement.

Tinea: This is the infection of the skin caused by fungus, mainly in the areas of feet, groin or hands. The fungus of the feet is referred to as Athletes foot. Treatment is by Antifungal agents

Psoriasis: There are hardening and shrinking of the connective tissue of the skin which is characterised by red, scaly patches on the skin. There might be joint pain in a few cases. The treatment is via administration of topical steroids in most cases of psoriasis.

Urticaria: This is an allergic reaction in which red, round wheals develop on the skin causing itching. The treatment is by a hydrocortisone cream or antihistamines.

Carcinoma(Skin Cancer): The two common forms of skin cancer are the squamous cell carcinoma and basal cell carcinoma which involve the excessive growth of the cells of the epidermal layer. Some of the symptoms of skin cancer include abnormal lumps or spots on the skin. Popularly treated via Mohs surgery, skin cancer is the main issue for people who spend too much time in the sun.