Dermatitis herpetiformis ( DH ) is a chronic blistering skin condition, characterized by abrasions filled with aqueous liquids. Despite its name, DH is not associated with or caused by the herpes virus: its name means that skin inflammation has a similar appearance to herpes.
Herpetiform dermatitis was first described by Louis Adolphus Dühring in 1884. The association between DH and celiac disease was recognized in 1967, although the exact cause mechanism was unknown. DH is a specific manifestation of celiac disease.
The age of onset is usually about 15-40, but DH can also affect children and the elderly. Men and women are affected equally. Estimates of DH prevalence vary from 1 in 400 to 1 in 10,000. It is most common in northern European/northern Indian descent patients, and is associated with HLA-DQ2 human antigen (HLA) haplotype along with celiac disease and gluten sensitivity.
Video Dermatitis herpetiformis
Signs and symptoms
Herpetiform dermatitis is characterized by severe itchy and chronic papulovesicular eruptions, usually symmetrically distributed on extensor surfaces (buttocks, neck, scalp, elbows, knees, back, hairline, groin, or face). Blisters vary in size from very small to 1 cm.
This condition is very itchy, and the desire to scratch may be overwhelming. This sometimes causes the sufferer to scratch the blisters before being examined by the doctor. The intense itchiness or burning sensation is sometimes felt before the blisters appear in certain areas.
Untreated, the severity of DH can vary significantly over time, in response to the amount of digested gluten.
Symptoms of herpetiformis dermatitis usually first appear in the early years of adulthood between 20 and 30 years.
Although the first signs and symptoms of dermatitis herpetiformis are very itchy and burning, the first signs seen are small papules or vesicles that usually look like red lumps or abrasions. Rashes rarely occur in other mucous membranes, except the mouth or lips. Symptoms range in severity from mild to serious, but they tend to disappear if gluten consumption is avoided and appropriate treatment is given.
The symptoms of herpetiform dermatitis are chronic, and they tend to come and go, mostly in short periods of time. Occasionally, these symptoms may be accompanied by symptoms of celiac disease, usually including abdominal pain, bloating or loose stools, and fatigue.
The rash caused by dermatitis herpetiformis is formed and disappears in three stages. In the first stage, the patient may notice slight discoloration on the skin where the lesion appears. At a later stage, the skin lesions change into clear vesicles and papules that may occur in the group. The healing of the lesion is the last stage of development of symptoms, usually characterized by discoloration of the skin. This can cause the skin area to become darker or lighter than the skin color throughout the body. Because of the intense itching, patients usually scratch, which can lead to the formation of the crust.
Maps Dermatitis herpetiformis
Pathophysiology
In the case of pathology, the first signs of the condition can be observed in the dermis. Possible changes at this level may include edema, blood vessel dilatation, and cellular infiltration. It is common for lymphocytes and eosinophils to be seen. The bulls found in the skin affected by dermatitis herpetiformis are subepidermal and have a rounded lateral border.
When looking under a microscope, the skin affected by dermatitis herpetiformis presents a collection of neutrophils. They have an increased prevalence in areas where the dermis is closest to the epidermis.
Direct IMF studies of unrelated skin showed IgA in dermal papilla and patchy granular granules along the basement membrane. The jejunal mucosa may exhibit partial partial atrophy, but changes tend to be milder than in celiac disease.
Immunology studies reveal findings similar to celiac disease in terms of autoantigen. The primary autoantigen of dermatitis herpetiformis is epidermal transglutaminase (eTG), a cytosolic enzyme involved in the formation of envelope cells during keratinocyte differentiation.
Various studies have demonstrated different potential factors that may play a greater or lesser role in the development of dermatitis herpetiformis. The fact that eTG has been found in skin-bound IgA deposits that are affected by this condition has been used to conclude that dermatitis herpetiformis can be caused by the deposition of both IgA and eTG in the dermis. It is estimated that this deposit can absorb after ten years after a gluten-free diet. In addition, it is suggested that this condition is closely related to genetics. This theory is based on the argument that individuals with a family history of gluten sensitivity who still consume gluten-containing foods are more likely to develop the condition as a result of antibody formation to gluten. These antibodies react cross with the eTG complex, and IgA/eTG in the papillary dermis to cause dermatitis herpetiformis lesions. These IgA deposits can disappear after a long period (up to ten years) avoiding diet gluten.
Gliadin proteins in gluten are absorbed by the intestine and into the lamina propria where they need to be mediated by the transglutanimase tissue (TTG). TTG modifies gliadin into a more immunogenic peptide. Classical dendritic cells (cDCs) endocytose peptides are immunogenic and if their pattern recognition receptors (PRRs) are stimulated by molecular patterns related to pathogens (PAMP) or danger-related molecular patterns (DAMP), hazard signals will affect them to secrete IL- 8 (CXCL8) in lamina propria, recruiting neutrophils. Recruitment of neutrophils produces a very rapid onset of inflammation. Therefore, co-infection with microbes carrying PAMP may be necessary for early onset of symptoms in gluten sensitivity, but will not be necessary for consecutive meetings with gluten due to the production of memory B and memory T cells (discussed below).
Herpetiform dermatitis can be characterized by inflammation of the skin and intestines. Inflammation in the intestine is similar to, and associated with, celiac disease. TTG is treated as an autoantigen, especially in people with HLA-DQ2 and HLA-DQ8 alleles and other gene variants that cause atopy. TTG is regulated after gluten uptake. cDCs endocytose tTG-modified gliadin complexes or self modified gliadin but they only present gliadin to CD4 T cells in the pMHC-II complex. These T cells become active and polarized into T type I (Th1) cells. Th1 cells reactive to gliadin have been found, but none against TTG. A naive sequence of naive tTG-gliadin complex cells modified from the surface of cDCs in lymph nodes (LNs) before they become endocytosed by cDCs. B cell receptors (membrane bound antibody, BCR) are specific to the TTG portion of the complex. Cell B endocytoses are complex and present a modified gliadin to activated T1 cell cell receptor (TCR) through pMHC-II in a process known as spreading epitope. Thus, cell B presents an alien peptide (modified gliadin) but produces antibodies specific to self antigen (TTG). Once B cell is activated, it will differentiate into plasma cells that secrete autoantibodies against TTG, which may be cross-reactive with epidermal transglutanimase (eTG). Class A (IgA) antibodies enter the intestine. Some may bind to CD89 receptors (Fc? RI) on macrophages (M1) through their Fc region (constant region). This will trigger the endocytosis of the tTG-IgA complex, resulting in macrophage activation. Macrophages secrete more IL-8, spreading neutrophil-mediated inflammatory responses.
The autoantibodies supposedly cross-reactive can migrate to the skin in herpetiform dermatitis. IgA deposition may form if antibodies react with the epidermal transglutanimase (eTG). Some patients have specific eTG antibodies rather than specific tTG cross-reactive antibodies and the association between dermatitis herpetiformis and celiac disease in these patients is not fully understood. Macrophages can be stimulated to secrete IL-8 by the same process as seen in the intestine, causing neutrophils to accumulate in place of high eTG concentrations in skin dermal papilla. Neutrophils produce pus on the dermal papilla, producing distinctive blisters. The accumulation of IL-31 in the blisters can increase the itching sensation. Memory B and T cells may become active in the absence of PAMP and DAMP during successive encounters with modified gliadin modified tTG or gliadin alone, respectively. Symptoms of herpetiform dermatitis are often resolved if the patient avoids a gluten-rich diet.
Diagnosis
Herpetiformis dermatitis is often misdiagnosed, becoming confused with drug eruptions, contact dermatitis, dysphyrosis eczema (dyshidrosis), and even scabies.
The diagnosis can be confirmed by simple blood testing for IgA antibodies against transglutaminase tissue (which cross-reacts with transglutaminase epidermal), and with skin biopsies in which the IgA deposit pattern in the dermal papilla, expressed by direct immunofluorescence, differentiates it from linear IgA bleeding dermatosis and other forms of dermatitis. These tests should be performed before the patient starts a gluten-free diet, otherwise they may produce a false negative. Like regular celiac disease, IgA against transglutaminase disappears (often within months) when patients remove gluten from their diet. Thus, for both groups of patients, it may be necessary to restart gluten for several weeks before testing can be performed reliably. In 2010, Cutis reported an eruption labeled gluten-sensitive dermatitis that is clinically indistinguishable from herpetiform dermatitis, but lacks IgA connections, similar to gastrointestinal symptoms that mimic the disease celiac but without diagnostic immunological markers.
Treatment
Strict gluten-tight diets should be followed, and usually, this treatment will be a lifelong need. Avoiding gluten will reduce associated bowel damage and the risk of other complications.
Dapsone is an effective early treatment for most people. Itching usually decreases within 2-3 days; however, dapsone treatment has no effect on possible bowel damage. After some time on a gluten-free diet, dose dapsone can usually be reduced or even stopped, although this may take years. Dapsone is an antibacterial, and its role in the treatment of DH, which is not caused by bacteria, is poorly understood. This can cause adverse effects on blood, so regular blood monitoring is required.
Dapsone is the drug of choice. For individuals with DH can not tolerate dapsone for any reason, alternative treatment options may include the following:
- colchicine
- lymecycline
- nicotinamide
- tetracycline
- sulfamethoxypyridazine
- sulfapyridine
Prognosis
Herpetiform dermatitis generally responds well to treatment and changes in diet. It is an autoimmune disease, however, and patients with DH are more likely than others to have thyroid and intestinal lymphoma problems.
Dermatitis herpetiformis usually does not cause its own complications, without being associated with other conditions. The complications of this condition, however, arise from the autoimmune character of the disease, as excessive immune system is a sign that something is not working properly and may cause problems to other parts of the body that do not necessarily involve the digestive system.
Gluten intolerance and body reactions to it make the disease more worrying in what concerns the possibility of complications. This means that the possible complications arising from dermatitis herpetiformis are similar to those resulting from celiac disease, which includes osteoporosis, certain types of colon cancer, and an increased risk of other autoimmune diseases such as thyroid disease.
The risk of developing complications from dermatitis herpetiformis decreases significantly if the affected individuals follow a gluten-free diet. This disease has been linked to autoimmune thyroid disease, insulin dependent diabetes, lupus erythematosus, SjÃÆ'¶gren syndrome, sarcoidosis, vitiligo, and alopecia areata.
Famous cases
It has been suggested that a French revolutionary Jean-Paul Marat possessed DH, guided him to spend most of his time, and even worked from, a bathtub full of herbs he used as palliative for canker sores.
See also
- Pemphigus herpetiformis
- List of skin conditions
References
Further reading
- KÃÆ'¡rpÃÆ'¡ti S (2012). "Dermatitis herpetiformis". Clinic in Dermatology (Review). 30 (1): 56-9. doi: 10.1016/j.clindermatol.2011.03.010. PMID 22137227.
External links
- Picture: Elbow Arms
- Image: DermNet NZ
- Image: Gastrolab Image Library
- Image: mediscan
- DH's extensive and varied photo collection at Iowa University Hardin Library for Health Sciences
- DermNet immunity/dermatitis-herpetiformis
- A collection of articles from Celiac.com
- Journal of Investigative Dermatology
- Medline Plus
Source of the article : Wikipedia
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