Alopecia (atrichia with papular lesions, APL) [Q84.0]
Dipl.-Biol. Birgit Busse
Hair loss (alopecia) occurs in different, phenotypically distinguishable forms that partially have a strong genetic component. APL (atrichia with papular lesions) is a very rare and special type of genetic hair loss, that is caused by mutations in the hairless gene (HR). So far, these mutations have mostly been found in families of the Arab regions. Patients show papular lesions with complete hair loss distributed all over the body and cystic malformations in the hair follicles. Affected children are born with hair, however, lose it soon after birth. Unlike other forms of genetic hair loss (Alopecia areata, Alopecia universalis), APL is resistant to conventional therapy (corticosteroid, cyclosporine or PUVA therapy). Therefore, a differential diagnosis in the form of a HR gene analysis prior to therapy may be useful to determine APL or another type of alopecia as the cause of hair loss. The MX1 gene may be analysed as well in order to differentiate it from androgenic alopecia.
Alopecia areata is a special form of hair loss that is based on a chronic, autoimmunologic inflammation. This type is associated with HLA-DR11 and HLA-DQ*03.