Loose anagen hair syndrome in two patients with epidermolysis bullosa simplex, Dowling-Meara type

Alopecia in Autoimmune Blistering Diseases: A Systematic Review of Pathogenesis and Clinical Features of Disease

Background

Autoimmune blistering diseases (AIBD) are characterised by the body's production of autoantibodies against structural proteins in the epidermis and/or the basement membrane on cutaneous and mucosal surfaces. Alopecia is a complication of AIBD that has generally been overlooked in patients with severe blistering diseases because it is regarded as a cosmetic issue. Yet recent research into quality of life tools has found that stigmatisation by appearance plays a significant role in blistering diseases.

Aim

To review the current literature detailing the pathogenesis and clinical presentations of alopecia in AIBD patients.

Method

We searched Medline, PubMed and EMBASE electronic databases up to September 2018, for empirical human and animal studies.

Results

Only 36 human studies including 223 patients (190 pemphigus, 25 pemphigoid, 5 epidermolysis bullosa acquisita, 2 dermatitis herpetiformis and 1 linear IgA disease) detailed demographic and clinical manifestations of alopecia. A range of hair evaluation methods was demonstrated to reach alopecia diagnosis. Furthermore, with no universal validated scoring system for alopecia severity, alopecia patterns have been summarised.

Conclusion

Previous randomised trials have not highlighted alopecia as an important outcome of AIBD, so epidemiological evaluation of the available literature has been helpful in summarising trends between existing studies and demonstrating inconsistencies.

Pathogenesis and clinical features of alopecia in epidermolysis bullosa: A systematic review

BACKGROUND

Epidermolysis bullosa (EB) is a group of rare genetic skin diseases characterized by the gene mutations encoding adhesion proteins within the skin. These adhesion proteins are also present in normal hair follicles. Anecdotally, there have been reports of scalp alopecia as a complication of EB and there are scattered cases in the literature, but alopecia has generally been overlooked in severe blistering diseases because it is regarded as a cosmetic issue. Therefore, there is no consensus about the natural history and clinical manifestations of alopecia in EB to allow potential intervention.

OBJECTIVES

To review the current literature detailing the pathogenesis and clinical presentations of alopecia in EB patients.

METHODS

Relevant human studies were searched in Medline, PubMed, and EMBASE electronic databases up to October 2018.

RESULTS

Only 15 reports detailed 29 EB patients with demographic and clinical manifestations of alopecia. Vertical biopsy sections were the most common method of alopecia diagnosis, and the most common pattern was patchy scalp alopecia (45%) followed by diffuse alopecia (41%). The most robust finding was nonspecific scarring alopecia in all dystrophic EB (DEB) patients and nonspecific nonscarring alopecia in most patients with EB simplex (EBS).

CONCLUSIONS

Hair abnormalities observed in EB are of variable severity despite there being no universal validated alopecia scoring system, with alopecia occurring secondary to blistering, or in areas prone to trauma.