Last updated:
March 10, 2026
Dermatitis herpetiformis is a chronic, pruritic, autoimmune, blistering skin condition. It is the cutaneous manifestation of coeliac disease. It presents as clusters of small vesicles or papules on the extensor surfaces (elbows, knees, and buttocks).
It peaks at 30 – 40 years and is more common in men.
- Risk factors
- HLA D12 and HLA DQ8
- Exposure to gluten
- Coeliac disease (80% have varying degrees of gluten-sensitive enteropathy)
- Male sex
- Pathophysiology
- Gliadin peptides are indigestible in genetically susceptible individuals
- They cross the intestinal epithelium and interact with tissue transglutaminase, forming deamidated gliadin-tTG complexes
- Anti-tTG IgA antibodies are formed against these complexes. The tantibdies cross-react with epidermal transglutaminase (eTG) found in the dermal papillae
- Deposition of IgA-eTG immune complexes in the dermal papillae causes inflammation → subepidermal blister formation (manifesting as vesicles and bullae)
- Mast cells release histamine, causing intense pruritus
- Signs and symptoms
- Symmetrical, erithematous and intensely pruritic papules and vesicles
- Distributed over extensor surfaces (elbows, knees, and buttocks)
- Excoriation and crusting due to scratching
- Differentials
- Bullous pemphigid
- Linear IgA disease
- Investigations
- Skin biopsy: granular IgA deposits in the dermal papillae
- Serology to detect IgA anti-tTG antibodies and IgA anti-endomysial antibodies
- Upper gastrointestinal endoscopy with small bowel biopsy: for villous atrophy and crypt hyperplasia
- Treatment
- Gluten-free diet
- Dapsone to relieve pruritus
- Sulfapyridine and colchicine in patients who cannot tolerate dapsone
- Complications
Biochemistry
| ACTH | P: <80 ng/L |
| ALT | P: 5–35 U/L |
| Albumin | P: 35–50 g/L |
| Aldosterone | P: 100–500 pmol/L |
| Alk. phosphatase | P: 30–130 U/L |
| α-Amylase | P: 0–180 IU/dL |
| α-Fetoprotein | S: <10 kU/L |
| Angiotensin II | P: 5–35 pmol/L |
| ADH | P: 0.9–4.6 pmol/L |
| AST | P: 5–35 U/L |
| Bicarbonate | P: 24–30 mmol/L |
| Bilirubin | P: 3–17 μmol/L |
| BNP | P: <50 ng/L |
| CRP | P: <10 mg/L |
| Calcitonin | P: <0.1 mcg/L |
| Calcium (ionized) | P: 1.0–1.25 mmol/L |
| Calcium (total) | P: 2.12–2.60 mmol/L |
| Chloride | P: 95–105 mmol/L |
| Cholesterol | P: <5.0 mmol/L |
| VLDL | P: 0.128–0.645 mmol/L |
| LDL | P: <2.0 mmol/L |
| HDL | P: 0.9–1.93 mmol/L |
| Cortisol AM | P: 450–700 nmol/L |
| Cortisol Midnight | P: 80–280 nmol/L |
| CK ♂ | P: 25–195 U/L |
| CK ♀ | P: 25–170 U/L |
| Creatinine | P: 70–100 μmol/L |
| Ferritin | P: 12–200 mcg/L |
| Folate | S: 2.1 mcg/L |
| FSH | P: 2–8 U/L ♂; >25 menopause |
| GGT ♂ | P: 11–51 U/L |
| GGT ♀ | P: 7–33 U/L |
| Glucose (fasting) | P: 3.5–5.5 mmol/L |
| Growth hormone | P: <20 mu/L |
| HbA1C (DCCT) | B: 4–6% |
| HbA1C (IFCC) | B: 20–42 mmol/mol |
| Iron ♂ | S: 14–31 μmol/L |
| Iron ♀ | S: 11–30 μmol/L |
| Lactate (venous) | P: 0.6–2.4 mmol/L |
| Lactate (arterial) | P: 0.6–1.8 mmol/L |
| LDH | P: 70–250 U/L |
| LH | P: 3–16 U/L |
| Magnesium | P: 0.75–1.05 mmol/L |
| Osmolality | P: 278–305 mosmol/kg |
| PTH | P: 0.8–8.5 pmol/L |
| Potassium | P: 3.5–5.3 mmol/L |
| Prolactin ♂ | P: <450 U/L |
| Prolactin ♀ | P: <600 U/L |
| PSA | P: 0–4 mcg/mL |
| Protein (total) | P: 60–80 g/L |
| Red cell folate | B: 0.36–1.44 μmol/L |
| Renin (erect) | P: 2.8–4.5 pmol/mL/h |
| Renin (recumbent) | P: 1.1–2.7 pmol/mL/h |
| Sodium | P: 135–145 mmol/L |
| TBG | P: 7–17 mg/L |
| TSH | P: 0.5–4.2 mU/L |
| T4 | P: 70–140 nmol/L |
| Free T4 | P: 9–22 pmol/L |
| TIBC | S: 54–75 μmol/L |
| Triglycerides | P: 0.50–2.3 mmol/L |
| T3 | P: 1.2–3.0 nmol/L |
| Troponin T | P: <0.1 mcg/L |
| Urate ♂ | P: 210–480 μmol/L |
| Urate ♀ | P: 150–390 μmol/L |
| Urea | P: 2.5–6.7 mmol/L |
| Vitamin B12 | S: 0.13–0.68 nmol/L |
| Vitamin D | S: 50 nmol/L |
Arterial Blood Gases
| pH | 7.35–7.45 |
| PaCO₂ | 4.7–6.0 kPa |
| PaO₂ | >10.6 kPa |
| Base excess | ±2 mmol/L |
Urine
| Cortisol (free) | <280 nmol/24h |
| Hydroxyindole acetic acid | 16–73 μmol/24h |
| Hydroxymethylmandelic acid | 16–48 μmol/24h |
| Metanephrines | 0.03–0.69 μmol/mmol cr. |
| Osmolality | 350–1000 mosmol/kg |
| 17-Oxogenic steroids ♂ | 28–30 μmol/24h |
| 17-Oxogenic steroids ♀ | 21–66 μmol/24h |
| 17-Oxosteroids ♂ | 17–76 μmol/24h |
| 17-Oxosteroids ♀ | 14–59 μmol/24h |
| Phosphate (inorganic) | 15–50 mmol/24h |
| Potassium | 14–120 mmol/24h |
| Protein | <150 mg/24h |
| Protein/creatinine ratio | <3 mg/mmol |
| Sodium | 100–250 mmol/24h |
Haematology
| WCC | 4.0–11.0 ×10⁹/L |
| RBC ♂ | 4.5–6.5 ×10¹²/L |
| RBC ♀ | 3.9–5.6 ×10¹²/L |
| Hb ♂ | 130–180 g/L |
| Hb ♀ | 115–160 g/L |
| PCV ♂ | 0.4–0.54 L/L |
| PCV ♀ | 0.37–0.47 L/L |
| MCV | 76–96 fL |
| MCH | 27–32 pg |
| MCHC | 300–360 g/L |
| RDW | 11.6–14.6% |
| Neutrophils | 2.0–7.5 ×10⁹/L (40–75%) |
| Lymphocytes | 1.0–4.5 ×10⁹/L (20–45%) |
| Eosinophils | 0.04–0.44 ×10⁹/L (1–6%) |
| Basophils | 0–0.10 ×10⁹/L (0–1%) |
| Monocytes | 0.2–0.8 ×10⁹/L (2–10%) |
| Platelets | 150–400 ×10⁹/L |
| Reticulocytes | 0.8–2.0% / 25–100 ×10⁹/L |
| Prothrombin time | 10–14 s |
| APTT | 35–45 s |
Paediatric
| Pulse Rate (bpm) |
|---|
| Neonate | 140–160 |
| Infant <1yr | 120–140 |
| 1–5 years | 110–130 |
| 5–12 years | 80–120 |
| >12 years | 70–100 |
| Respiratory Rate (tachypnoea) |
|---|
| 0–2 months | ≥60/min |
| 2–12 months | ≥50/min |
| 1–5 years | ≥40/min |
| >5 years | ≥30/min |
| Blood Pressure (mmHg) |
|---|
| Term | 65/45 |
| 1 year | 75/50 |
| 4 years | 85/60 |
| 8 years | 95/65 |
| 10 years | 100/70 |
| Weight Formulas |
|---|
| 3–12 months | (a + 9)/2 kg |
| 1–6 years | 2a + 8 kg |
| >6 years | (7a − 5)/2 kg |
| Haemoglobin (g/dL) |
|---|
| Term newborn | 13–20 |
| 1 month | 11–18 |
| 2 months | 10–15 |
| 1–2 years | 10–13 |
| >2 years | 11–14 |
| MUAC (6 months–5 years) |
|---|
| Obese | >17.5 cm |
| Normal | 13.5–17.4 cm |
| At risk | 12.5–13.4 cm |
| Moderate malnutrition | 11.5–12.4 cm |
| Severe malnutrition | <11.5 cm |
| Developmental Milestones |
|---|
| Social smile | 1.5 months |
| Head control | 4 months |
| Sits unsupported | 7 months |
| Crawls | 10 months |
| Stands unsupported | 10–12 months |
| Walks | 12–13 months |
| Talks | 18 months |
| CSF WBC (/mm³) |
|---|
| Term newborn | 0–25 |
| >2 weeks | 0–5 |
