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Notes: The anatomy of the epidermis, dermis and subcutaneous tissues of the nail apparatus is distinct from that of non-appendageal skin. Apart from the demonstration of the longitudinal configuration of the dermal-epidermal junction of the nail bed, there have been no studies of the composition of the basement membrane zone of the nail apparatus. We obtained three human accessory digits, including one thumb, all of which had been amputated for cosmetic reasons, and were without known pathology. Specimens were stained with a battery of monoclonal and polyclonal antibodies which target normal basement membrane zone antigens, and studied by indirect immunoflourescence.This study demonstrated that the four distinct regions of the nail, namely the proximal nail fold, the nail matrix, the nail bed and the hyponychium expressed all the target antigens found in the normal non-appendageal basement membrane. In particular, there was normal expression of the epidermal-associated antigens, the 220-and 180-kDa bullous pemphigoid antigens, and the α6β4 integrin. There was also normal expression of the lamina lucida antigens LH39, GB3 and laminin. It is of interest that the dermal-associated components, namely the 285-kDa linear IgA antigen, the extracellular matrix glycoproteins chondroitin sulphate, type VII collagen and its closely associated proteins, and the poorly characterized antigen for LH24 and LH39 were all normally expressed.Fibronectin, which is not a normal basement membrane zone component, was diffusely expressed in the extracellular matrix, but did not accentuate the basement membrane zone. LHF2, an antibody raised against tenascin, which shows weak positive staining at the tips of dermal papillae in normal skin (unpublished data) diffusely stained the extracellular matrix and the tips of the dermal papillae of the nail matrix and hyponychium, but did not stain the basement membrane of the nail bed.These findings show that despite the numerous distinct features of epidermis, dermis and subcutis of the nail apparatus, the basement membrane zone has virtually identical antigen expression to that of the dermal-epidermal junction elsewhere. The difference in LHF2 expression in the nail bed most likely reflects the different shape of the nail bed basement membrane, which is arranged in longitudinal folds.

Notes: Summary Loose anagen syndrome (LAS) is a condition of childhood where anagen hairs are easily and painlessly extracted. The condition is due to poor adhesion between the cuticle of the hair shaft and the inner root sheath. A 4-year-old girl presented with patches of hair loss and a clinical diagnosis of trichotillomania was made. A hair pull test extracted multiple hairs easily and painlessly. Light microscopic examination was consistent with LAS. A biopsy was performed, which showed features of trichotillomania. However, on request the child did not display sufficient dexterity to pull out her own hair. It was subsequently determined that her hair loss was likely to be due to a third person plucking out her hair. It appears that in this case the LAS was not the cause of her hair loss, but rather acted as a severity factor for trichotillomania by proxy in that the lack of pain on plucking the hairs removed the principle deterrent.