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Dermatologic Disorders

Approach to the Dermatologic Patient
Principles of Topical Dermatologic Therapy
- Principles of Topical Dermatologic Therapy
Acne and Related Disorders
Bacterial Skin Infections
Benign Skin Tumors, Growths, and Vascular Lesions
Bullous Diseases
Cancers of the Skin
Cornification Disorders
Dermatitis
Fungal Skin Infections

Hair Disorders
Hypersensitivity and Inflammatory Disorders
Nail Disorders
Parasitic Skin Infections
Pigmentation Disorders
Pressure Ulcers
- Pressure Ulcers
Psoriasis and Scaling Diseases
Reactions to Sunlight
Sweating Disorders
Viral Skin Diseases

Although skin lesions may represent only a dermatologic disorder, the skin often serves as a marker for underlying internal disease, such as internal cancers, endocrinopathies, and GI disorders. Although the history and physical examination are often adequate for diagnosing many skin lesions, good clinical acumen is essential and diagnostic tests are sometimes needed.

Dermatologic DisordersSections (A-Z)

Acne and Related Disorders

Acne vulgaris is the formation of comedones, papules, pustules, nodules, and/or cysts as a result of obstruction and inflammation of pilosebaceous units (hair follicles and their accompanying sebaceous gland). Acne develops on the face and upper trunk. It most often affects adolescents. Diagnosis is by examination. Treatment, based on severity, can involve a variety of topical and systemic agents directed at reducing sebum production, comedone formation, inflammation, and bacterial counts and at normalizing keratinization.

Acne Vulgaris
Hidradenitis Suppurativa
Perioral Dermatitis
Rosacea

Approach to the Dermatologic Patient

History and physical examination are adequate for diagnosing many skin lesions . Some require biopsy or other testing.

Evaluation of the Dermatologic Patient
Description of Skin Lesions
Diagnostic Tests for Skin Disorders
Itching
Urticaria
Skin Manifestations of Internal Disease

Bacterial Skin Infections

Bacterial skin infections may be uncomplicated or complicated. Uncomplicated infections usually respond promptly to systemic antibiotics and local wound care. A skin infection is considered complicated when it meets 2 of the following 5 criteria:

Overview of Bacterial Skin Infections
Cellulitis
Erysipelas
Cutaneous Abscess
Folliculitis
Furuncles and Carbuncles
Erythrasma
Impetigo and Ecthyma
Lymphadenitis
Lymphangitis
Necrotizing Subcutaneous Infection
Staphylococcal Scalded Skin Syndrome

Benign Skin Tumors, Growths, and Vascular Lesions

Atypical moles are benign melanocytic nevi with irregular and ill-defined borders, variegated colors usually of brown and tan tones, and macular or papular components. Patients with atypical moles have an increased risk of melanoma . Management is by close clinical monitoring and biopsy of highly atypical or changed lesions. Patients should reduce sun exposure and conduct regular self-examinations for new moles or changes in existing ones.

Atypical Moles
Capillary Malformations
Cutaneous Cysts
Dermatofibromas
Infantile Hemangiomas
Keloids
Lipomas
Lymphatic Malformations
Moles
Nevus Araneus
Pyogenic Granulomas
Seborrheic Keratoses
Skin Tags
Vascular Lesions of the Skin

Bullous Diseases

Bullae are elevated, fluid-filled blisters ≥ 10 mm in diameter.

Introduction to Bullous Diseases
Bullous Pemphigoid
Dermatitis Herpetiformis
Epidermolysis Bullosa Acquisita
Linear Immunoglobulin A Disease
Mucous Membrane Pemphigoid
Pemphigus Foliaceus
Pemphigus Vulgaris

Cancers of the Skin

Skin cancer is the most common type of cancer and commonly develops in sun-exposed areas of skin. The incidence is highest among outdoor workers, sportsmen, and sunbathers and is inversely related to the amount of melanin skin pigmentation; fair-skinned people are most susceptible. Skin cancers may also develop years after therapeutic x-rays or exposure to carcinogens (eg, arsenic ingestion).

Overview of Skin Cancer
Atypical Fibroxanthoma
Basal Cell Carcinoma
Bowen Disease
Kaposi Sarcoma
Keratoacanthoma
Melanoma
Merkel Cell Carcinoma
Paget Disease of the Nipple
Squamous Cell Carcinoma

Cornification Disorders

Calluses and corns are circumscribed areas of hyperkeratosis at a site of intermittent pressure or friction. Calluses are more superficial, cover broader areas of skin, and usually asymptomatic. Corns are deeper, more focal, and frequently painful. Diagnosis is by appearance. Treatment is with manual abrasion with or without keratolytics. Prevention involves altering biomechanics, such as changing footwear. Rarely, surgery is required.

Calluses and Corns
Ichthyosis
Keratosis Pilaris
Palmoplantar Keratodermas
Xeroderma

Dermatitis

Dermatitis is superficial inflammation of the skin characterized by

Definition of Dermatitis
Atopic Dermatitis (Eczema)
Contact Dermatitis
Exfoliative Dermatitis
Hand and Foot Dermatitis
Lichen Simplex Chronicus
Nummular Dermatitis
Seborrheic Dermatitis
Stasis Dermatitis

Fungal Skin Infections

Candidiasis is skin infection with Candida sp, most commonly Candida albicans . Infections can occur anywhere and are most common in skinfolds, digital web spaces, genitals, cuticles, and oral mucosa. Symptoms and signs vary by site. Diagnosis is by clinical appearance and potassium hydroxide wet mount of skin scrapings. Treatment is with drying agents and antifungals.

Candidiasis (Mucocutaneous)
Overview of Dermatophytoses
Tinea Barbae
Tinea Capitis
Tinea Corporis
Tinea Cruris
Tinea Pedis
Dermatophytid Reaction
Intertrigo
Tinea Versicolor

Hair Disorders

Alopecia
Alopecia Areata
Hirsutism
Pseudofolliculitis Barbae

Hypersensitivity and Inflammatory Disorders

The immune system plays a significant role in a large number of skin disorders, including dermatitis, sunlight reactions, and bullous diseases. Although all of these disorders involve some level of inflammation, certain skin disorders are primarily characterized by their inflammatory component or as a hypersensitivity reaction, be it to a drug, infection, or cancer.

Introduction to Hypersensitivity and Inflammatory Disorders
Acute Febrile Neutrophilic Dermatosis
Drug Eruptions and Reactions
Erythema Multiforme
Panniculitis
Erythema Nodosum
Granuloma Annulare
Pyoderma Gangrenosum
Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)

Nail Disorders

A variety of disorders can affect nails, including deformities , infections of the nail , paronychia , and ingrown toenails . Nail changes may occur in many systemic conditions and genetic syndromes or result from trauma.

Overview of Nail Disorders
Nail Deformities and Dystrophies
Onychomycosis
Acute Paronychia
Chronic Paronychia
Ingrown Toenail

Parasitic Skin Infections

Bedbug bites are usually painless but cause reactions, often pruritic, in susceptible patients.

Bedbugs
Cutaneous Larva Migrans
Cutaneous Myiasis
Delusional Parasitosis
Lice
Scabies

Pigmentation Disorders

Pigmentation disorders involve hypopigmentation, depigmentation, or hyperpigmentation. Areas may be focal or diffuse. In hypopigmentation, pigment is decreased, whereas in depigmentation, pigment is completely lost, leaving white skin.

Overview of Pigmentation Disorders
Albinism
Vitiligo
Hyperpigmentation

Pressure Ulcers

Pressure ulcers (PUs) are areas of necrosis and ulceration where tissues are compressed between bony prominences and hard surfaces. They are caused by pressure in combination with friction, shearing forces, and moisture. Risk factors include age > 65, impaired circulation, immobilization, undernutrition, and incontinence. Severity ranges from nonblanchable skin erythema to full-thickness skin loss with extensive soft-tissue necrosis. Diagnosis is clinical. Prognosis is excellent for early-stage ulcers; neglected and late-stage ulcers pose risk of serious infection and are difficult to heal. Treatment includes pressure reduction, avoidance of friction and shearing forces, and diligent wound care. Sometimes, skin grafts or myocutaneous flaps are needed to facilitate healing.

Pressure Ulcers

Principles of Topical Dermatologic Therapy

Topical dermatologic treatments are grouped according to their therapeutic functions and include

Principles of Topical Dermatologic Therapy

Psoriasis and Scaling Diseases

Psoriasis is an inflammatory disease that manifests most commonly as well-circumscribed, erythematous papules and plaques covered with silvery scales. Multiple factors contribute, including genetics. Common triggers include trauma, infection, and certain drugs. Symptoms are usually minimal, but mild to severe itching may occur. Cosmetic implications may be major. Some people develop severe disease with painful arthritis. Diagnosis is based on appearance and distribution of lesions. Treatment can include topical treatments (eg, emollients, vitamin D analogs, retinoids, coal tar, anthralin, corticosteroids), phototherapy, and, when severe, systemic drugs (eg, methotrexate, oral retinoids, cyclosporine, immunomodulatory agents [biologics]).

Psoriasis
Lichen Planus
Lichen Sclerosus
Parapsoriasis
Pityriasis Lichenoides
Pityriasis Rosea
Pityriasis Rubra Pilaris

Reactions to Sunlight

The skin may respond to sunlight with chronic (eg, dermatoheliosis [photoaging] , actinic keratosis ) or acute (eg, photosensitivity , sunburn ) changes.

Overview of Effects of Sunlight
Chronic Effects of Sunlight
Photosensitivity
Sunburn

Sweating Disorders

There are two types of sweat glands: apocrine and eccrine.

Introduction to Sweating Disorders
Bromhidrosis
Hyperhidrosis
Hypohidrosis
Miliaria

Viral Skin Diseases

Molluscum contagiosum is characterized by clusters of pink, dome-shaped, smooth, waxy, or pearly and umbilicated papules 2 to 5 mm in diameter caused by molluscum contagiosum virus, a poxvirus. Diagnosis is based on clinical appearance. Treatment aims to prevent spread or remove cosmetically unacceptable lesions and can include mechanical methods (eg, curettage, cryosurgery) and topical irritants (eg, imiquimod, cantharidin, tretinoin).