Page 168 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 5-5 Integumentary System

CELIAC SPRUE AND DERMATITIS HERPETIFORMIS
DERMATITIS HERPETIFORMIS Physical findings Diagnostic evaluation

Dermatitis herpetiformis is a unique chronic blistering
disease that can be seen in isolation or in conjunction Glossitis, aphthous stomatitis
with celiac sprue. Dermatitis herpetiformis is the cuta- (failure of absorption of
neous manifestation of underlying gluten sensitivity. water-soluble B vitamins)
Patients with a genetic predisposition seem to be at risk
for development of immunoglobulin A (IgA) autoanti-
bodies that cross-react with gluten proteins and specific Atrophy of jejunal mucosa
components of the skin and gastrointestinal tract. Der- demonstrated by small
matitis herpetiformis is always associated with small- Osteoporosis, osteomalacia, bowel biopsy
bowel disease, and in some cases celiac sprue coexists. tendency to fractures
Patients with dermatitis herpetiformis are at increased (hypocalcemia, vitamin D Tissue transglutaminase
risk for development of lymphoma of the gastrointesti- deficiency) and endomysial antibodies
nal tract, potentially caused by the chronic inflamma-
tion and stimulation of the gastrointestinal-associated Wasting (failure of absorption
lymphatic tissue. Following a gluten-free diet cures the of fats, carbohydrate, proteins)
disease in both the skin and gastrointestinal locations.
Clinical Findings: Dermatitis herpetiformis is most Tetany (hypocalcemia)
frequently seen in the fourth and fifth decades of life,
with a higher prevalence in the female Caucasian popu-
lation. The reason for this preference may be that der- Dermatitis herpetiformis
matitis herpetiformis has associations with the human (fragile vesicles)
leukocyte antigen (HLA) DQ2 and DQ8 haplotypes.
Dermatitis herpetiformis manifests as a symmetric Abdominal distention (bulky
vesicular eruption, which is often preceded by a burning stools, potassium depletion)
sensation or pruritus. The extensor surfaces of the 72-hour
elbows, knees, and lower back, as well as the scalp, may Dehydration (diarrhea) stool fat
be involved. The vesicles are fragile and break easily.
Erosions and excoriations are frequently seen. Diarrhea Ecchymoses (failure of
can be a recurrent complaint, secondary to involvement absorption of vitamin K)
of the small bowel. Patients frequently report a flare of
the rash and abdominal pain and diarrhea after eating Infantile
certain foods. Steatorrhea, diarrhea (intestinal celiac
Laboratory testing is frequently performed. High stimulation and irritation due disease
levels of IgA anti–tissue transglutaminase (anti-tTG) to bulk of unabsorbed fat and
antibody and antiendomysial antibodies (EMAs) are to abnormal intestinal flora)
commonly found and are highly specific for dermatitis
herpetiformis. In cases of suspected sprue, an upper Edema (hypoproteinemia)
endoscopy can be performed, with a biopsy of the small
bowel to evaluate for the characteristic villous atrophy.
Pathogenesis: Dermatitis herpetiformis is an auto-
immune blistering disease that is caused by the develop-
ment of specific antibodies, notably anti-tTG and
EMAs. Tissue transglutaminase (tTG) is very similar to
epidermal transglutaminase, and it is believed that the
anti-tTG antibodies attack both proteins. This disrup-
tion of the epidermal transglutaminase is thought to be
responsible for the blistering skin findings. Once the
antibodies attach to the epidermal transglutaminase
protein, the complement cascade and various cytotoxic
cellular events are activated. The anti-EMA test is the
most specific of the antibody tests for dermatitis
herpetiformis.
Histology: Early lesions of dermatitis herpetiformis
show subepidermal clefting with a neutrophil-rich infil-
trate in the papillary dermis. As the lesions progress,
subepidermal blistering becomes prominent, and the
papillary dermis is filled with neutrophils. The histo- Neutrophilic infiltrate underlying a subepidermal blister
logical findings of dermatitis herpetiformis can be dif-
ficult to differentiate from those of linear IgA bullous the itching and blistering. This can be rapidly achieved treat the blistering and pruritus, but they do not
dermatosis on routine hematoxylin and eosin staining. with dapsone or sulfapyridine. The response to these decrease the long-term risk of small-bowel lymphoma.
Direct immunofluorescence is required to differentiate two medications is remarkably quick, with most The only means of decreasing and removing the risk
the two diseases. The direct immunofluorescence stain- patients noticing near-resolution of their symptoms of lymphoma is to have the patient adhere to a strict
ing pattern in dermatitis herpetiformis is that of a speck- within 1 day. In cases of suspected dermatitis herpeti- gluten-free diet. This requires nutritional education. If
led arrangement of IgA within the papillary dermis. In formis that has not been confirmed histologically, patients are able to entirely avoid gluten-containing
linear IgA bullous disease, as the name implies, a linear dapsone can be used as a therapeutic test: If the patient products, not only will the rash resolve, but the gas-
pattern along the basement membrane zone is seen. sees a rapid response after the first day of dapsone trointestinal abnormalities will resolve, and the risk
Treatment: The treatment of dermatitis herpetifor- therapy, the diagnosis is most certainly dermatitis her- of lymphoma will return to that of the general
mis is twofold. The first aspect of therapy is to control petiformis. Dapsone or alternative medications can population.

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