Page 228 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 8-5 Integumentary System

MAIN SOURCES, CAUSES, AND SKIN FINDINGS OF PELLAGRA
PELLAGRA
Principal sources of niacin Principal sources of tryptophan

Pellagra is caused by inadequate dietary intake of niacin Whole
(nicotinic acid, vitamin B 3 ) or its precursor amino acid, wheat
tryptophan. It has also been discovered to occur on bread
occasion in patients with carcinoid syndrome. In this Meats, Eggs Milk
syndrome, tryptophan is used entirely to produce sero- especially liver Whole grain cereals
tonin, and there is none left to produce niacin. Pellagra Principal causes of pellagra
was first identified as a unique disease in the early 1700s
by a Spanish physician, Gaspar Casal, who observed it Corn and
in Spanish peasants who ate diets almost entirely made molasses Alcohol
of corn and corn-based foodstuffs. He named the diet diet
disease “Asturian leprosy” after the region of Spain he
was studying. An Italian physician, Francesco Frapoli,
who studied the disease in endemic regions of northern
Italy, later named it pellagra. Deficiency of both
Pellagra has been dominant in regions of the world niacin and tryptophan
that rely heavily on corn as the main dietary staple. In
the early twentieth century, the southern United States
was inundated with cases of pellagra. Joseph Gold-
berger, a physician and epidemiologist studying the
disease, discovered that pellagra was caused directly by
a deficiency of vitamin B. He was unable at that time
to isolate the specific B vitamin, but he has been given
credit for discovering the cause of pellagra.
Clinical Findings: Pellagra can affect any individual
regardless of race or gender. The incidence in the
North America and Europe is low, and cases are mainly
caused by abnormal diets and alcoholism. The disease
can still be seen in endemic regions of the world where
corn is the main food source. The clinical cutaneous
hallmark of pellagra is a severe dermatitis. The derma-
titis is photosensitive, and exposure to the sun often
brings out the rash or exacerbates it. Patients often
present initially after having spent many hours outdoors
on an early spring day. The dermatitis is symmetric and Facial
is manifested by eczematous patches and thin plaques lesions;
that tend to be tender to the touch. There is a fine line Casal’s Glove-and-stocking lesions
of demarcation between abnormal and normal skin. necklace;
The head, neck, and arms are the most involved regions dementia
because of their higher level of sun exposure. The der-
matitis along the anterior neck and upper thorax has
been termed Casal necklace. This is represented by
weeping pink and red patches and plaques in a distribu-
tion like that of a necklace touching the skin circumfer-
entially around the neck. Because of its photosensitive
nature, the dermatitis of pellagra often spares the skin
directly behind the ears and beneath the chin. The
nose, forehead, and cheeks are prime regions of involve-
ment. Non–sun-exposed areas can also be involved,
and the intertriginous regions are almost universally
affected, including the perineum, axillae, and inframam-
mary skin folds. The reason for the propensity to affect
these non–sun-exposed regions is poorly understood
but may be related to chronic friction that induces the
dermatitis. In the areas of involvement, small vesicula-
tions may occur because of separation of the epidermis
from the dermis.
As time progresses, the dermatitis begins to desqua-
mate. This process begins in the central portions of the
dermatitis and spreads outward in a centrifugal manner.
As the skin desquamates, it leaves behind red, eroded
patches and plaques. Chronic involvement leaves per-
manent scarring and abnormal hyperpigmentation or with atrophied papillae are seen routinely in patients Diarrhea is commonplace and is caused by the effect
hypopigmentation of the area. The epidermis over with pellagra. The oral and gastrointestinal mucous of niacin deficiency on the gastrointestinal tract. The
bony prominences (e.g., ulnar head) shows marked membranes may be involved. Oral ulcerations are fre- diarrhea is watery and further complicates the patient’s
hyperkeratosis. quently seen. Patients routinely complain of a sore nutritional status and electrolyte and fluid balances.
Mucous membrane involvement is common in all mouth and difficulty swallowing; these symptoms can Blood and purulence may be present in the watery diar-
vitamin deficiency states, and pellagra is no exception. lead to further lack of proper nutrition, exacerbating rhea as a result of ulceration and abscess formation.
Angular cheilitis and a red, shiny, edematous tongue and compounding the disease. Ulcerations can be seen throughout the gastrointestinal

214 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS