Medical Blog

What is vitiligo, and what causes it?

Vitiligo (vit-ill-EYE-go) is a pigmentation disorder in which melanocytes (the cells that make pigment) in the skin are destroyed. As a result, white patches appear on the skin in different parts of the body. Similar patches also appear on both the mucous membranes (tissues that line the inside of the mouth and nose), and the retina (inner layer of the eyeball). The hair that grows on areas affected by vitiligo sometimes turns white.
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Introduction
Background

Sjögren-Larsson syndrome (SLS) is a rare autosomal recessive neurocutaneous disorder characterized by mental retardation, diplegia or tetraplegia, and congenital ichthyosis. The ichthyosis (usually evident at birth) may be seen in some patients after the first year of life.
Pathophysiology

SLS is due to deficient activity of fatty aldehyde dehydrogenase (FALDH), an enzyme required to oxidize fatty alcohol to fatty acid. It catalyzes the oxidation of medium- and long-chain fatty aldehydes to their corresponding carboxylic acids. The gene encoding FALDH is called the ALDH3A2 gene (or ALDH10) and has been mapped to the SLS locus on band 17p11.2. Current results show a large variety of mutant alleles carrying different mutations (>70), including amino acid substitutions, deletions, insertions, and splicing errors in this gene.
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Sarcoidosis
Background

Sarcoidosis is a multisystem disorder of unknown cause which can affect any organ of the body taking the form of cells which cluster together in tiny nodules, or sarcoid granulomas. These are clusters of chronic inflammatory cells.

Sarcoidosis can develop in almost any organ. Most commonly it attacks the lungs, eyes, skin, more rarely the brain and nervous system. It can also spread to other organs such as the liver, heart and kidneys. The disease can range from a mild, self-limiting condition which needs no treatment, to a severe, chronically progressive illness. Children usually recover from sarcoidosis, but this may take some years.
What are the symptoms? Read more…

Kaposi’s Sarcoma

Kaposi’s sarcoma is a specific type of cancer that involves the tissues of the skin or the coverings of blood vessels.
What is going on in the body?

Kaposi’s sarcoma , or KS, usually begins in certain skin cells. These cells undergo cancerous changes and begin to grow uncontrollably. For people with intact immune systems, the cancer grows slowly, if at all, and rarely spreads. The disease becomes very aggressive if the person has an impaired immune system. HIV infections and drugs given after organ transplant will suppress the immune system. Until AIDS became widespread, KS was rarely seen. KS is common in people with AIDS.
What are the causes and risks of the disease? Read more…

Systemic Sclerosis
Introduction
Background

Systemic sclerosis (SSc) is a systemic connective tissue disease. Characteristics of SSc include essential vasomotor disturbances; fibrosis; subsequent atrophy of the skin, subcutaneous tissue, muscles, and internal organs (eg, alimentary tract, lungs, heart, kidney, CNS); and immunologic disturbances accompany these findings. Read more…

Cellulitis
Introduction
Background

Cellulitis is an acute infection of skin and soft tissues characterized by localized pain, swelling, tenderness, erythema, and warmth.

The eMedicine Emergency Medicine article Cellulitis and the Medscape CME course Managing the Complicated Skin and Soft Tissue Infection may be of interest.
Pathophysiology Read more…

Blepharitis
Blepharitis is an inflammation of the eyelid. It develops at the place where the mucous membrane on the underside of the lid joins the skin on the top of the lid. It occurs in both children and adults. The condition can be chronic and recur.
What is going on in the body?

The margin of the lid becomes inflamed along the eyelash line. Redness, scaling, and sometimes an infection can develop in the skin between the eyelashes.
What are the causes and risks of the disease?
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Atopic Eczema - Eczema
Eczema is a skin condition that causes patches of dry, scaly, extremely itchy skin.
What is going on in the body?

Eczema usually results from a hypersensitivity, or allergy-like sensitivity, causing inflammation. The inflammation causes the skin to become itchy and scaly. Eczema is not a true allergy. Rather, it is a condition in which the skin may react or become sensitive to allergens, which are allergy-causing substances.
What are the causes and risks of the condition?
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Atopic Dermatitis
Introduction
Background

Atopic dermatitis (AD) is a pruritic disease of unknown origin that usually starts in early infancy (an adult-onset variant is recognized); it is characterized by pruritus, eczematous lesions, xerosis (dry skin), and lichenification (thickening of the skin and an increase in skin markings). AD may be associated with other atopic (immunoglobulin E [IgE]) diseases (eg, asthma, allergic rhinitis, urticaria, acute allergic reactions to foods).1 AD has enormous morbidity, and the incidence and prevalence appear to be increasing. Other conditions with different etiologies and prognoses are often grouped under the umbrella of a diagnosis of AD.
Pathophysiology

Good evidence indicates that genetic factors are important in the development of atopic dermatitis (AD), but the pathophysiology is still poorly understood. Two main hypotheses have been proposed regarding the development of the inflammatory lesions. The first suggests an immune dysfunction resulting in IgE sensitization and a secondary epithelial-barrier disturbance. The second proposes a defect in epithelial cells leading to the defective barrier problem, with the immunological aspects being epiphenomena. Read more…