Skin Is the Window to Your Health
If you compare your body to a book, your skin is the dust jacket. By examining the title, looking over the cover image, and reading the liner notes, you can often determine what might be going on inside. So, if you look carefully, you can tell quite a bit about the internal workings of your body by examining your skin.
The distribution of a rash is often helpful in coming up with a list of possible diseases (differential diagnosis). For example, a rash on the cheeks that involves the bridge of the nose can be a sign of a number of conditions, including rosacea, seborrheic dermatitis, contact dermatitis, and lupus erythematosus. Although the distributions may be identical, other findings enable your doctor to differentiate these conditions. Only lupus generally involves the internal organs.
The presence of this "dirty brown" coloring is not due to melanin pigmentation but to an abnormally thickened epidermis called acanthosis nigricans. In a young, overweight individual, it may signal a predisposition to diabetes. In an elderly person who appears ill, it may be an ominous sign of an internal malignancy.
Leg Plaque: Red on Edge, Gold in Center
Necrobiosis lipoidica characteristically appears on the shin(s) and has a vaguely circular shape and a brown-yellow color. It often appears to be depressed. Many but not all of those afflicted have diabetes. The presence of this condition and the control of the diabetes are not directly related.
Itchy, Violet Bumps on Wrist
Lichen planus can affect both the skin and the mucous membranes. It is typically itchy. It appears as small, flat-topped brown to gray bumps with some scaling. Although very uncommon, there may be some association with hepatitis C infection. Most patients are healthy with no internal disease.
Flesh Colored, Orange-Peel Patches on Back
These white patches are devoid of color and often first noted soon after birth. To some doctors with a botanical bent, they look like ash leaves. They are only one of a number of skin findings found in a rare systemic disease called tuberous sclerosis. This very serious genetic condition may involve the brain and kidneys. Sometimes the skin findings are so subtle even those affected may not be aware of their existence. Due to an increased understanding of its molecular cause, there are drugs that can improve its symptoms, which include seizures and mental retardation.
Tripe is boiled beef or pig stomach. How closely these palms resemble tripe is debatable, but this term has stuck nevertheless. This peculiar thickening of the palms is often associated with acanthosis nigricans and signals the likely association of an internal malignancy.
"Wooden" Hands and Feet
This peculiar thickening of the skin of the arms and legs is unique to some patients who are in renal failure and who have had imaging studies enhanced with gadolinium chloride. This contrast agent is no longer used in patients with poor kidney function, so this condition ought to be vanishingly rare.
Scaly Rash on Buttocks, Red Tongue
Necrolytic migratory erythema is not an easy diagnosis to make. The skin eruption is rather nonspecific and tends to occur in the folds of the groin, the buttocks, and around the mouth. The tongue can be quite sore. It is often confused with a simple fungal infection at first. A pathological examination of a skin biopsy from the rash can be quite helpful. The patient often has an elevated blood sugar because this rash comes from a tumor in the pancreas that produces glucagon.
Not All Skin Conditions Are Scary
Granuloma annulare is not rare. Typical lesions are asymptomatic and ring-shaped with a bumpy edge that can gradually extends outward over a period of months. Most of those afflicted are otherwise healthy.