Epidermolysis bullosa simplex, Dowling-Meara type

Alternate names

EBS-DM; Dowling-Meara type epidermolysis bullosa simplex; Epidermolysis bullosa herpetiformis, Dowling-Meara type; Epidermolysis bullosa simplex, herpetiformis

Definition

Epidermolysis bullosa simplex, Dowling-Meara type (EBS-DM) is a basal subtype of epidermolysis bullosa simplex (EBS) characterized by the presence of generalized vesicles and small blisters in grouped or arcuate configuration.

Epidemiology

Worldwide prevalence is unknown but reported prevalence in Scotland is 1/1,700,000.

Cause

EBS-DM is caused by dominant negative mutations within either the KRT5 (12q13.13) or KRT14 (17q12-q21) genes, encoding keratin 5 and keratin 14, respectively.

Inheritance

Autosomal dominant pattern, a 50/50 chance.

Transmission is autosomal dominant and sporadic cases are frequent.

Onset

Onset is usually at birth with large, frequently hemorrhagic blisters.

Signs and symptoms

• After the neonatal period, the lesions take the typical herpetiform (or herpes-like) clustering with central healing pattern.
• Blister formation gradually reduces starting from late childhood.
• By childhood, most patients begin to develop confluent thickening and hyperkeratosis (keratoderma) of the palms and soles which may partially resolve in some patients during mid- to late-adulthood.
• Along with blisters, skin findings commonly include mild atrophic scarring and post-inflammatory pigmentation, nail shedding and nail dystrophy, as well as occasional milia formation.
• Lesions may improve in some patients in case of fever, unlike other forms of EB in which warmer weather exacerbates disease activity. The reason for this is unknown.
• Extracutaneous complications can occur including oral cavity blistering, constipation and, rarely, tracheolaryngeal compromise.

Diagnosis

The diagnosis of epidermolysis bullosa simplex (EBS) is established in a proband by the identification of heterozygous (or rarely biallelic) pathogenic variants in KRT5 or KRT14 by molecular genetic testing; examination of a skin biopsy using immunofluorescence microscopy and transmission electron microscopy may be considered but can have limitations in the diagnosis of EBS.[1].

Treatment

• Supportive care to protect the skin from blistering; use of dressings that will not further damage the skin and will promote healing of open wounds.
• Lance and drain new blisters.
• Dressings involve three layers: a primary nonadherent contact layer; a secondary layer providing stability, adding padding, and absorbing drainage; and a tertiary layer with elastic properties.[2].

NIH genetic and rare disease info

• NIH info on Epidermolysis bullosa simplex, Dowling-Meara type

Epidermolysis bullosa simplex, Dowling-Meara type is a rare disease.