Which is the most common age group affected by bullous pemphigoid?

Explanation

## Age of Onset in Bullous Pemphigoid **Key Point:** Bullous pemphigoid is predominantly a disease of the **elderly**, with peak incidence in patients >60 years of age. The disease is rare in children and young adults. ### Age Distribution and Epidemiology | Age Group | Incidence | Clinical Notes | | --- | --- | --- | | **>60 years** | Peak incidence (most common) | 60–80% of cases | | 40–60 years | Moderate incidence | ~20–30% of cases | | 20–40 years | Uncommon | <5% of cases | | <20 years | Rare | <1% of cases (childhood BP exists but very rare) | ### High-Yield Facts **High-Yield:** Bullous pemphigoid is the **most common autoimmune blistering disorder in the elderly**, surpassing pemphigus vulgaris in this age group. The incidence increases sharply after age 60. ### Clinical Pearl **Clinical Pearl:** An elderly patient (>65 years) presenting with tense bullae on flexural surfaces should raise immediate suspicion for bullous pemphigoid. This is one of the classic presentations in geriatric dermatology. ### Pathophysiology of Age Predilection The age predilection is attributed to: 1. **Waning immune tolerance** — declining regulatory T cell function with age 2. **Molecular mimicry** — cross-reactivity between BP180 and BP230 antigens and environmental antigens increases with cumulative antigen exposure 3. **Genetic susceptibility** — HLA-DQ5 and HLA-DQ7 associations are more prevalent in elderly populations 4. **Comorbidities** — medications (diuretics, NSAIDs) and systemic diseases may trigger or exacerbate disease **Mnemonic:** **ELDERLY BP** = Elderly patients, Lesions flexural, Dermal-epidermal separation, Rare in youth, Linear IgG/C3 on immunofluorescence, Young adults spared. **Warning:** Do not confuse with pemphigus vulgaris, which shows a broader age range (30–60 years most common) and is not as strongly age-restricted to the elderly. [cite:Robbins 10e Ch 25]