Hidradenitis suppurativa : clinical studies with focus on evaluation

Abstract

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of mainly unknown aetiology which in most cases involves axillae or groins and that can last for decades. In this thesis different clinical aspects of HS are studied: development of a clinical scoring system, relation to smoking and obesity, outcome of laser surgery, bacteraemia in HS patients and distribution of the neuroendocrine marker protein gene product (PGP) 9.5 in HS skin biopsies.

In Paper I the objective is to evaluate the modified Hidradenitis Suppurativa Score (HSS) and to study the impact of BMI and smoking habits on disease severity. Altogether 246 HS patients completed the Dermatology Life Quality Index (DLQI) questionnaire and 115 were scored by HSS. Points were given for regions, types of lesion (nodules, fistulas), total area involved, and whether lesions were separated by normal skin. A positive correlation of fair degree between HSS and DLQI was found, as well as significant higher median scores in more advanced HS, in smokers compared to non smokers and in obese women compared to those of normal weight, respectively. The results indicate that the HSS reflects disease severity, and may be a relevant outcome measure in clinical trials.

In Paper II scanner-assisted carbon dioxide laser treatment with subsequent healing by secondary intention is evaluated in 34 HS patients, with in total 67 operating sites. They were interviewed by telephone about recurrences and end results, after a mean follow-up time of 34.5 (range 7 87) months. Four patients had had recurrences in one of the treated areas. In twelve cases, lesions had developed separated from the initial surgical site by >5 cm. Twenty-five patients had flare-ups of HS lesions in another anatomical region. Eight had no symptoms of HS at all during the follow-up period. Mean healing time was 4 (range 3 5) weeks. The conclusion is that scanner-assisted carbon dioxide laser treatment of HS is an efficient treatment, well accepted by the patients.

In Paper III the objective is to determine the number and type of bacteria circulating in the bloodstream in HS patients undergoing carbon dioxide laser surgery. Blood samples were taken before, during and after surgery in 21 patients with HS Hurley stage II, and from five healthy controls. Bacterial growth in the first blood sample was found in nine patients, from the second in ten and from the third in six. In one patient, bacteria were detected in all the three samples. The dominating bacteria were coagulase- negative staphylococci, of which most were subtyped as S. warneri. In six patients all samples were negative, which may indicate that the method of surgery itself caused no spread of bacteria.

In Paper IV the presence and distribution of the nerve fibre-marker PGP 9.5 is investigated by immunohistochemistry. Biopsies were taken from the groin or axilla of 16 HS patients and 12 healthy controls. The median number of PGP 9.5 positive profiles was decreased in lesional epidermis, yet statistically significant only in the groin. A similar difference was found in lesional dermis of the axilla, whereas in the lesional upper dermis of the groin the median number of profiles was increased. Cells with strong PGP 9.5 immunofluorescence were few or absent in epidermis, but significantly increased in lesional dermal skin of the groin. It is possible that PGP 9.5 positive nerve fibres and cells have pathological roles in HS, but further investigations are needed.