What is dermatology?

Definition

Dermatology is the medical discipline that is concerned with the diagnosis and treatment of diseases of the skin, hair, and nails in both children and adults. Specialists in dermatology are called dermatologists.

The New Zealand Dermatological Society’s definition is comprehensive:

“Dermatology involves but is not limited to study, research, and diagnosis of normal and disorders, diseases, cancers, cosmetic and ageing conditions of the skin, fat, hair, nails and oral and genital membranes, and the management of these by different investigations and therapies, including but not limited to dermatohistopathology, topical and systemic medications, dermatologic surgery and dermatologic cosmetic surgery, immunotherapy, phototherapy, laser therapy, radiotherapy and photodynamic therapy.”

How many people get skin disease?

The skin is the largest and most visible organ of the body. It reflects the health of the body and acts as a barrier against injury and bacteria.

Skin disorders are the fourth most frequent cause of all human disease, affecting between 30–70% of people worldwide. Most people develop some type of skin disease during their life, from infants to the elderly, and this is one of the leading reasons to seek medical advice in all societies.

What are the different fields of dermatology?

There are many fields and subspecialties within dermatology, including (but not limited to):

• Medical dermatology – includes dealing with medical conditions such as dermatitis, psoriasis, urticaria, connective tissue diseases, skin infections, disorders of pigmentation, skin conditions associated with internal diseases, and acne and rosacea in both adults and children (paediatric dermatology).
• Surgical dermatology – deals mostly with treating and removing skin lesions such as melanoma, non-melanoma skin cancer (NMSC), and other non-cancerous lesions by a variety of modalities including curettage and cautery, cryotherapy, excisional surgery and photodynamic therapy. This field also includes Mohs micrographic surgery.
• Cosmetic dermatology – focusing on the cosmetic treatment of skin, hair, and nail conditions. This includes laser treatments, removal of scars, hair implants, injectable fillers, and botulinum toxin (Botox).

What are the most common skin disorders?

Common skin diseases include:

• Skin cancer
• Warts
• Skin infections: fungal, viral (eg, herpes simplex), and bacterial
• Dermatitis — one in six children develop atopic dermatitis (eczema)
• Psoriasis
• Acne — a common condition affecting adolescents worldwide
• Hand dermatitis — resulting from external contact with detergents and household chemicals, affects most homemakers with young families
• Alopecia (hair loss) – autoimmune disease that affects 2% of people worldwide.

Dermatological examinations and procedures

See Dermatological investigations and tests for more detail.

Dermoscopy

A dermatoscope is a handheld medical device that employs a magnification illuminated lens system that assists in the identification and diagnosis of skin lesions.

Microbiology samples

A swab can be taken from skin lesions with exudate or fluid to be examined for viral and bacterial cultures.

Skin scraping

A sample of scaly skin can be taken by scraping a disposable scalpel blade 90 degrees to the skin to collect surface dead skin cells for fungal examination.

Skin biopsy

This includes removal of a skin sample from the lesion of interest to be sent for histopathological examination. It is performed under local anaesthesia. There are different methods for taking a skin biopsy – including a shave biopsy, punch biopsy, or excision biopsy. It is useful in diagnosing many skin diseases including skin cancers and blistering skin conditions.

Intralesional steroid injection

The injection of steroids into the skin is used in the management of different conditions such as hypertrophic or keloid scars, acne cysts, vitiligo, and alopecia.

Phototherapy

This includes using narrow band ultraviolet (UV) radiation in treating various skin conditions such as eczema (atopic dermatitis), psoriasis, vitiligo, and pruritus.

Research in dermatology

Research is an important component of dermatology, leading to many advances in the field and improved patient outcomes. Many dermatologists are involved in research, at both basic science and clinical levels.