Celiac can manifest itself in many ways. For some individuals, their symptoms occur on the skin in a condition known as dermatitis herpetiformis (DH). In these instances, the path to a celiac diagnosis begins with the diagnosis of DH.
Dermatitis Herpetiformis Symptoms
DH has a specific set of symptoms. Patients will have “bumps or blisters…clustered together…[that] appear bilaterally on the forearms, elbows, knees, buttocks and hairline,” explains Robyn Gmyrek, M.D., board-certified dermatologist at Union Square Laser Dermatology in New York. The “bilateral” appearance she refers to means that a patient’s DH symptoms will develop, for example, on both knees.
According to Nicole Seminara, M.D., assistant professor in the Ronald O. Perelman Department of Dermatology at NYU Langone Medical Center, the bumps and blisters characteristic of DH are “intensely itchy [and] people usually scratch them off before they ever present to a doctor.” As a result, Seminara says, “It’s uncommon to see an intact blister with this disorder.”
Instead, patients’ skin will “look like [it has] been scratched to pieces,” notes Seminara. When no bumps or blisters are present, “it’s more the history of intense itch coupled with the distribution that leads us to the diagnosis [of DH]. The diagnosis is then confirmed with a biopsy.” Another important aspect of DH is age. It tends to develop in patients who are in their 30s or 40s.
The Celiac Link
The connection between DH and celiac is something dermatologists “are very aware of…and take very seriously,” says Seminara. “If I have a patient with DH,” she says, he or she is “always sent to [a gastroenterologist]” to be tested for celiac.
“The great majority of patients with DH have celiac disease as defined by duodenal biopsy showing villous atrophy,” explains Benjamin Lebwohl, M.D., M.S., director of clinical research at The Celiac Disease Center at Columbia University. “The remainder may have a normal- or near-normal-appearing duodenal biopsy but nevertheless have their DH triggered by dietary gluten, which is why DH is sometimes referred to as ‘celiac disease of the skin.'”
As is often the case with celiac symptoms, the potential for misdiagnosis is high. “This is because not all people with DH will have typical lesions, and the rash may come and go,” explains Gmyrek. The rash can be misidentified and “is commonly diagnosed as eczema or an allergic contact dermatitis by both patients and physicians.” She says that “if you have been diagnosed with eczema, have a lot of itching and you are not responsive to topical treatments…you should consider getting tested for celiac disease and biopsied to rule out DH.”
The Key to Relief
When it comes to healing DH, the gluten-free diet is key—as is patience. “[Patients] have to be very strictly gluten free, and [the healing is] a slow process,” says Seminara.
Gmyrek also emphasizes the importance of patients being aware of the healing timetable. “Patients need to know this because they expect that within a week or two of being gluten free, the rash will be gone or they will stop getting new lesions,” explains Gmyrek. That expectation can cause problems because when the lesions have not gone away soon after starting the diet, patients think “that they must somehow be getting gluten in their diet because the rash is not gone yet.” In fact, Gmyrek says, “It can take one to two years even with a strictly gluten-free diet for the skin rash to totally resolve.”
The drug Dapsone can help ease discomfort caused by the rash. “[Dapsone] decreases the body’s immune response and therefore the rash,” says Gmyrek. “Patients feel relief within 48 to 72 hours of taking this medication.” However, the drug does not replace a gluten-free diet. “Taking Dapsone does not cure DH [because] only a gluten-free diet forever will rid the patient of DH,” says Gmyrek.
Even when strictly adhering to the diet, skin lesions may still appear. Gmyrek points out that iodine, which is important to normal thyroid health, “will often cause skin lesions in patients with DH.” She emphasizes that “iodine does not adversely affect patients with celiac disease who do not have DH and should not be eliminated in those patients.” For those with DH, Gmyrek recommends that “patients use non-iodized table salt or sea salt, which has less iodine than iodized table salt, until their DH has resolved.”