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Diff: Dermatitis herpetiformis

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Dermatitis herpetiformis (DH) is a chronic autoimmune skin condition characterized by intensely itchy, blistering skin lesions. It is considered a cutaneous manifestation of celiac disease, an autoimmune disorder triggered by the ingestion of gluten. DH is relatively rare, affecting approximately 1 in 10,000 people.
	'''Dermatitis herpetiformis''' is an intensely itchy blistering skin condition linked to gluten sensitivity and coeliac disease. It is not caused by the herpes virus. The name refers to the clustered appearance of the blisters.

== Overview ==
Dermatitis herpetiformis is characterized by the presence of clusters of small, red, itchy blisters. The name "herpetiformis" refers to the appearance of the blisters, which may resemble those seen in herpes infections, although the two conditions are unrelated.
	The condition is a skin manifestation of gluten-driven autoimmunity. It can occur with or without obvious bowel symptoms, so people may not realise that their rash is linked to gluten.

== Symptoms ==	== Symptoms ==
The main symptom of dermatitis herpetiformis is the intense itching and burning sensation that accompanies the skin lesions. The blisters typically appear symmetrically on the elbows, knees, buttocks, and back, but can also occur on other parts of the body. Scratching the blisters may cause them to rupture and result in crust formation.
	Dermatitis herpetiformis usually causes very itchy bumps and small blisters. They often appear symmetrically on the elbows, knees, buttocks, scalp, shoulders or back. Scratching can break the blisters, leaving crusts, marks or excoriations.

Individuals with DH may also experience gastrointestinal symptoms similar to those of celiac disease, such as abdominal pain, bloating, diarrhea, and weight loss. However, these symptoms are often less pronounced in DH compared to celiac disease.
	The rash may come and go. Burning, stinging or intense itching can happen before visible lesions appear.

== Pathophysiology ==
The underlying cause of dermatitis herpetiformis is an immune reaction to gluten, specifically to the gluten protein fraction known as gliadin. When individuals with DH consume gluten, their immune system produces antibodies called IgA antibodies, which are deposited in the small blood vessels of the skin. The IgA antibodies activate immune cells in the skin, leading to the characteristic blistering and inflammation.
	Some people also have symptoms of coeliac disease, such as bloating, diarrhoea, abdominal pain, tiredness, anaemia or weight change, but many have few digestive symptoms.

The majority of individuals with DH also have celiac disease, and both conditions share a common genetic background and immune response to gluten. However, unlike celiac disease, DH primarily affects the skin rather than the gastrointestinal tract.
	== Cause ==
	The condition is triggered by gluten in people with genetic susceptibility. Gluten exposure can lead to IgA antibody deposits in the skin, which then drive inflammation and blistering.

	Dermatitis herpetiformis and coeliac disease are closely related. A person with dermatitis herpetiformis is usually treated as having gluten-sensitive disease even if bowel symptoms are mild.

== Diagnosis ==	== Diagnosis ==
Diagnosing dermatitis herpetiformis often involves a combination of clinical evaluation, skin biopsy, and blood tests. Skin biopsy is performed on a sample of uninvolved skin adjacent to a lesion, and the presence of specific IgA antibodies can be detected through immunofluorescence testing.
	Diagnosis is usually confirmed by a skin biopsy taken from normal-looking skin close to a blister. Direct immunofluorescence can show IgA deposits in a pattern typical of dermatitis herpetiformis.

In addition to confirming the diagnosis of DH, blood tests may also be conducted to detect other markers associated with celiac disease, such as tissue transglutaminase (tTG) antibodies or anti-endomysial antibodies (EMA).
	Blood tests for coeliac-related antibodies may also be used. Testing works best before a gluten-free diet has already been started, so people should speak to a clinician before removing gluten if dermatitis herpetiformis or coeliac disease is suspected.

== Treatment ==	== Treatment ==
The primary treatment for dermatitis herpetiformis is strict adherence to a gluten-free diet. Eliminating gluten from the diet helps prevent the immune reaction, leading to a resolution of skin lesions and alleviation of symptoms. It may take several months or longer for the skin to heal completely.

In some cases, medications may be prescribed to manage symptoms and speed up the healing process. These may include:
	The long-term treatment is a strict lifelong gluten-free diet. This reduces rash activity, helps the gut, and can reduce the need for medicine over time. Skin improvement can be slow, and it may take many months for the diet to have its full effect.

* Dapsone: A medication that helps control the itching and blistering. Dapsone is typically used in the short term until the gluten-free diet takes effect.
* Topical Corticosteroids: Creams or ointments containing corticosteroids can help reduce inflammation and relieve itching.
	Dapsone can reduce itch and blistering quickly, but it does not treat the underlying gluten sensitivity. People taking dapsone need medical monitoring because it can affect the blood and liver. Sulfapyridine or other medicines may be used where dapsone is not suitable.

Regular follow-up with a dermatologist and adherence to a gluten-free diet are essential for managing dermatitis herpetiformis and preventing further complications.
	Topical treatments may help with itch or inflammation, but they do not replace gluten avoidance.

== Complications and Outlook ==
Without proper treatment and adherence to a gluten-free diet, dermatitis herpetiformis can lead to long-term complications. These may include scarring, hyperpigmentation, and secondary infections resulting from scratching and open sores.
	== Living With the Condition ==
	Dietetic support is important because gluten-free living affects food choice, nutrition, cost, social eating and label reading. People may also need assessment for complications linked with coeliac disease, including nutritional deficiency and bone health problems.

With proper management, including a gluten-free diet and appropriate medications, individuals with dermatitis herpetiformis can expect significant improvement in their symptoms and skin lesions. However, lifelong adherence to a gluten-free diet is necessary to prevent recurrence of the condition.
	Accidental gluten exposure can trigger flares. The condition is chronic, but many people gain good control with a strict gluten-free diet and specialist follow-up.

== See Also ==	== See Also ==
	* [[Coeliac_Disease]]
	* [[Gluten_Sensitivity]]
	* [[Food_Intolerances]]
	* [[Autoimmune_Disorders]]

* [[Celiac Disease]] - Explore the autoimmune disorder triggered by gluten consumption, often associated with dermatitis herpetiformis.
* [[Gluten Sensitivity]] - Learn about adverse reactions to gluten-containing foods that do not involve an autoimmune response.
* [[Autoimmune Disorders]] - Understand a group of conditions where the immune system mistakenly attacks healthy cells and tissues.
	== References ==
	* [https://www.bad.org.uk/pils/dermatitis-herpetiformis-gluten-sensitivity British Association of Dermatologists: Dermatitis herpetiformis]
	* [https://dermnetnz.org/topics/dermatitis-herpetiformis DermNet: Dermatitis herpetiformis]
	* [https://www.pcds.org.uk/clinical-guidance/dermatitis-herpetiformis Primary Care Dermatology Society: Dermatitis herpetiformis]
	* [https://www.coeliac.org.uk/information-and-support/coeliac-disease/about-coeliac-disease-and-dermatitis-herpetiformis/ Coeliac UK: Coeliac disease and dermatitis herpetiformis]

	[[Category:Medicine]]
	[[Category:Dermatology]]
	[[Category:Autoimmune disease]]