1153
he skin serves as the interface between the body’s
internal organs and the external environment.
Therefore, skin disorders reflect a combination of envi-
ronmental and internal factors. Sunlight, infectious
organisms, chemicals, and physical agents all play a role
in the pathogenesis of skin diseases. Although most of
the disorders in this chapter are intrinsic to the skin and
its integuments, the hair and nails, these structures also
provide observable signs of many systemic disorders.
Primary Disorders of the Skin
A dermatosis is any skin condition involving acute or
chronic lesions or eruptions. Primary dermatoses are
those originating in the skin. They include infectious
processes, acne, rosacea, papulosquamous dermatoses,
allergic disorders, and drug reactions. Although most of
these disorders are not life-threatening, they can affect
the quality of life.
Infectious Processes
Normally, the skin flora, sebum, immune responses, and
other protective mechanisms defend against serious sys-
temic infections. However, the skin frequently succumbs
to attack by microorganisms, including fungi, bacteria,
and viruses.
Superficial Fungal Infections
Fungi are free-living, saprophytic, plantlike organisms,
certain strains of which are considered part of the nor-
mal skin flora (see Chapter 14). There are two types
of fungi: yeasts and molds. Yeasts, such as
Candida
albicans
, grow as single cells and reproduce asexually.
Molds grow in long filaments called hyphae. Fungal
infections of the skin or mycoses are commonly classi-
fied as deep or superficial.
1–3
Deep fungal infections of
the skin primarily involve the dermis and subcutaneous
tissue, and may extend into deeper tissues. In contrast,
superficial fungal infections, commonly known as tinea
T
Disorders of Skin
Integrity and
Function
46
C h a p t e r
Primary Disorders of the Skin
Infectious Processes
Superficial Fungal Infections
Bacterial Infections
Viral Infections
Pustular Disorders
Acne Vulgaris
Acne Conglobata
Rosacea
Allergic and Hypersensitivity Dermatoses
Atopic Dermatitis
Urticaria
Drug-Induced Skin Eruptions
Papulosquamous Dermatoses
Psoriasis
Pityriasis Rosea
Lichen Planus
Lichen Simplex
Skin Disorders due to Ultraviolet Radiation, Heat,
and Pressure Injury
Ultraviolet Radiation
Ultraviolet Radiation Skin Damage
Drug-induced Photosensitivity
Thermal Injury
Classification of Burns
Systemic Complications
Emergency and Long-Term Treatment
Pressure Ulcers
Mechanisms of Development
Prevention and Treatment
Nevi and Skin Cancers
Nevi
Skin Cancer
Malignant Melanoma
Basal Cell Carcinoma
Squamous Cell Carcinoma
Age-Related Skin Conditions
Skin Manifestations of Infancy and Childhood
Skin Disorders of Infancy
Pigmented and Vascular Birthmarks
Skin Manifestations of Common Infectious
Diseases
Skin Manifestations and Disorders in the Elderly
Normal Age-Related Changes
Skin Lesions Common Among the Elderly
