Condition: Epidermolytic Hyperkeratosis

Epidermolytic hyperkeratosis refers to hereditary skin disorders that are characterized by varying degrees of blistering and subsequent reactive scaling of the skin. Depending on the nature of the causative mutation, the symptoms may vary from mild blistering upon friction to severe erosions or widespread warty scaling (“porcupine man”). A palmoplantar keratoderma (excessive callus formation on palms and soles) and/or hair abnormalities may be present in some forms of the disorder. Rarely, EHK is part of a cardiocutaneous syndrome where cardiomyopathy and rhythm disturbances accompany the skin disorders (as for instance in Carvajal-Huerta syndrome).

A number of disorders show epidermolytic hyperkeratosis, including BCIE, ichthyosis bullosa Siemens and desmosomal disorders such as McGrath ectodermal dysplasia-skin fragility syndrome. Thus, in Europe, the term EHK is applied only to histopathological findings. However, in this entry, we follow American naming conventions and consider EHK synonymous with BCIE Brocq, a blistering disorder. In January 2009, an international ichthyosis consensus conference will hopefully end the confusion.