Introduction to Dermatology

Dermatology is the medical science of disorders of the skin. Often skin lesions and disorders are markers of internal disease and mirror the processes occurring within the body. Dermatology has been called "a window through which to see the entire body." As such an understanding of Dermatology is essential to the Internist.

Skin Anatomy
Skin consists of distinct layers. The most superficial (most exterior) layer is the epidermis. The epidermis is a stratified squamous epithelium. It has stacked layers of cells. Below the epidermis lies the dermis and below that we find the subcutaneous fat, or subcutis.

Epidermis
The epidermis consists of stratified squamous epithelium. The "bricks and mortar" cells of the epidermis are keratinocytes. Interspersed among the keratinocytes, we also find melanocytes and other specialized cells, known as Merkel cells. The keratinocytes provide the structure and maintain the barrier function of the skin. Melanocytes make protective pigment. Merkel cell function is less certain.

Skin Function
The primary functions of skin include protection from physical injury, impermeability (keeping fluids out of your body, and keeping necessary fluids inside of your body), resistance to microbial penetration, and function as a sensory end organ.

The secondary functions of skin include:


 * Immune Functions
 * Dryness, desquamation, normal flora of bacteria
 * Antigen presenting cells such as Langerhans cells, Keratinocytes (immunoregulating cytokine), Epidermotropic T-Cells.


 * Solar and Heat Interactions
 * UV Radiation Protection (melanin)
 * Thermoregulation
 * Vitamin D Metabolism


 * Communication

Functional Adaptations of Skin

 * Hair
 * Nails
 * Eccrine sweat glands
 * Apocrine glands
 * Sebaceous glands

Cellular Components of Skin

 * Epidermis
 * Keratinocytes
 * Langerhans cells
 * Melanocytes
 * Merkel cells
 * Lymphocytes


 * Dermis
 * Fibroblasts
 * Connective tissue
 * Extracellular proteins
 * Matrix
 * Endothelial cells
 * Mononuclear cells
 * Nerves and Neural organs


 * Hypodermis
 * Connective tissue
 * Adipocytes
 * Endothelial cells

Medical Disclaimer
= Pediatric Dermatologist = If your child has a skin condition such as a birthmark, eczema, acne, or psoriasis, a pediatric dermatologist will have the experience and qualifications to treat your child. Pediatric dermatologists treat a wide variety of pediatric skin conditions using the latest available treatments. Pediatric dermatologists treat children from birth through adolescence.

The pediatric dermatologist cares for children (newborns during adolescence) with skin disorders. Pediatric dermatologists treat children in a pediatric clinic setting, but they also care for hospitalized patients. Many people perform surgical procedures such as laser therapy and cataract surgery. Pediatric dermatologists Birthmarks (vascular and pigmented), skin diseases, dermatitis (atopic dermatitis, contact dermatitis), melanocytic navy blue (moles), genodermatosis (inherited skin disorders), acne breakouts, dermatitis, dermatitis Rash viral and vascular collagen disorders.