Hidradenitis suppurativa or acne inversa. A clinicopathological study of early lesions

Summary The pathogenesis of hidradenitis suppurativa (HS) has given rise to controversy about whether the central pathogenetic feature is an apocrine follicular occlusion (with subsequent bacterial infection) or it is a folliculitis with secondary involvement of both apocrine and eccrine sweat glands. Most previous concepts have focused on apocrine gland involvement. A prospective study of 27 consecutive patients (39 biopsies) was performed to investigate the immune-histological findings in early, newly formed lesions. Most of them were examined within 3 days of clinical onset. Histopathological findings showed that the initial lesion is an occluding spongiform infundibulofolliculitis. Furthermore, it was found that T cells predominated in the lymphocytic cell population. A high percentage of HLA-DR positive lymphocytes was found in an inverse relationship with Leu-8 positive lymphocytes. Additionally, a sharp decline in the T-helper/suppressor ratio was observed after the initiation. These results reveal that the primary event in HS is an infundibulofolliculitis with secondary involvement of apocrine glands. Acne inversa would be a more appropriate name.     

Hypopigmented lesions in early leprosy--a clinical and histological study

26 Patients of leprosy presenting with hypopigmented lesions were divided on morphological grounds into 3 Sub groups, Group I (9 patients) with well-defined single patch with moderate to complete sensory loss; Group II (8 patients) with single ill-defined lesion having partial sensory loss; and Group III (9 patients) having multiple hypo-pigmented patches with mild to moderate sensory loss. Epidermal atrophy was a conspicuous histological finding in all groups. Only patients in Group I showed epitheloid cells in dermal infiltrate with erosion of epidermis in one case. This group may be labelled as maculoanesthetic leprosy. Patients in Group II and III showed mononuclear cell infiltrate in dermis, around neurovascular bundles and appendages. They were histologically consistent with indeterminate leprosy. Follow-up biopsy after six to eight months of treatment showed healing of the lesion of reduction in the infiltrate in most cases.     

A retrospective study addressed to understanding what predicts severe histological dysplasia/early melanoma in excised atypical melanocytic lesions

BACKGROUND: Atypical naevi are common benign skin lesions but are also recognized both as precursors of and risk factors for melanoma. It is therefore imperative to excise those lesions that are either likely to progress or are already progressing to melanoma. Clinically, however, it may be difficult to distinguish these from benign atypical naevi with bland histology. OBJECTIVES: To analyse the clinical characteristics of excised melanocytic lesions and to identify the predictors of severe histological atypia/melanoma in situ and invasive melanoma. METHODS: The case notes of 434 patients who had melanocytic lesions removed at a pigmented lesion clinic were studied retrospectively. A single pathologist reviewed the excised lesions and clinical characteristics predictive of malignancy were identified. RESULTS: The best predictors of melanoma were older age, history of change and site on an extremity, but only older age was predictive of severe histological atypia/melanoma in situ as opposed to mild to moderate atypical histology. CONCLUSIONS: These results confirm the difficulty of differentiating accurately between benign atypical naevi and borderline lesions or early melanoma in a clinical setting. It is therefore necessary to have a sufficiently low threshold for excision to avoid missing early melanomas, particularly in older patients presenting with lesions on the extremities.     

Segmental acne versus mosaic conditions with acne lesions

Acne rarely presents in segmental patterns, which are encountered only in cutaneous mosaicism. We report herein two cases of segmentally arranged acne and systematically review the literature on the topic. Beside already known mosaic conditions which may show primary lesions typical of acne, i.e. nevus comedonicus, Happle-Tinschert syndrome, acne superimposed on epidermal nevi and mosaic Apert syndrome, we introduce the possibility that acne itself may present in a mosaic form. As from the extremely small casuistics retrieved, segmental acne is not present at birth, follows Blaschko lines, is polymorphous in nature and occurs on locations typical of common acne.     

A search for mycoplasmas and chlamydiae in acne lesions.

No mycoplasmas and no chlamydiae were found in cultures of 75 uninflamed comedones, 72 papulopustular lesions, and 7 cystic lesions from 14 subjects with acne. Chlamydial serologic tests were negative for 11 subjects and showed antibodies in 3 subjects to 3 different antigenic types of trachoma agent. These results are viewed as substantial evidence against the possibility that either mycoplasmas or chlamydiae play an important part in the pathogenesis of acne.     

Bone lesions in systemic acne (acne fulminans)

An 18-year-old West Indian male presented with severe sternal pain and an exacerbation of facial acne. Radiographs of the sternum revealed several lytic lesions which appeared as hot areas on successive technetium bone scans. Painful areas over the right iliac crest and left greater trochanter likewise appeared as transient hot areas on successive scans. Histology of affected bone revealed reactive changes only. High dose prednisolone provided rapid alleviation of pain, which recurred on reducing the dose to less than 10 mg daily. Auto-immune complex disease has been considered the most likely aetiological mechanism of systemic acne (acne fulminans), but lytic lesions of bone have never previously been reported in auto-immune disorders.     

A familial study of acne and eczema

The incidence of eczema was assessed in acne patients and their first degree relatives and compared with control (non-acne) subjects and their relatives. It was found that there was a statistically decreased incidence of endogenous eczema in the acne patients.     

Skin capacitance imaging of acne lesions

BACKGROUND: Little information is available about specific functional characteristics of skin in acneic patients. OBJECTIVE: To determine a capacitance mapping of lesional skin in acne in order to predict drug affinity according to the hydrophilic-lipophilic characteristics. METHOD: Skin capacitance imaging based on silicon image sensor technology was used with the SkinChip device. RESULTS: The non-optical images obtained by this means clearly identified low capacitance comedones contrasting with a perifollicular rim of high capacitance in inflammatory papules. This method also showed sweating and the follicular pores distributed in a pinpoint pattern. CONCLUSION: The objective mapping of skin surface capacitance showed large differences between acne lesions and the surrounding skin. The low capacitance of comedones contrasted with the high capacitance of the perifollicular area in inflammatory papules. These electrometric characteristics reflecting the corneocyte hydration may influence drug affinity to acne lesions.     

Macular atrophic lesions in acne vulgaris

Macular atrophic lesions coexisting with comedonal lesions are described in a case of acne vulgaris.     

Segmental neurofibromatosis: immunocytochemical analysis of cutaneous lesions

Cutaneous lesions from three patients with segmental neurofibromatosis were evaluated. Routine histologic studies revealed the presence of redimentary neural structures within an abundant collagenous matrix. The majority of the cells in all three cases expressed S-100 protein, suggesting their identity as Schwann cells. The stromal component stained positively for fibronectin and type IV collagen; the latter indicated the presence of basement membrane material. Embedded in the tumor mass were glandular epithelial structures that stained with epithelial membrane antigen antibody. Staining for factor VIII-related antigen revealed vascular endothelium and multiple scattered mast cells. In one case strands of cells stained with antibodies to desmin, suggesting muscle cell differentiation. This case may represent a distinct subset of neurofibromas.     

Pyogenic granuloma-like acne lesions during isotretinoin therapy

Three male patients with severe nodulocystic acne were treated with oral isotretinoin in a dosage of 0.5 to 1.0 mg/kg/day. A flare of their disease developed, characterized by an inflammatory, hemorrhagic, pyogenic, granuloma-like response of previously crusted acne lesions. This reaction occurred between the sixth and ninth weeks of treatment and was confined entirely to the chest and back. The severity of the reaction prompted the administration of oral prednisone and, in two cases, the discontinuation of isotretinoin therapy. In one patient, pyoderma gangrenosum developed on the thigh. The exact incidence of this pyogenic, granuloma-like reaction to isotretinoin is unknown, although we have seen it in three of 66 patients with nodulocystic acne treated with this drug. The cause of the reaction is unknown, but it may be due to the increased skin fragility and vascular proliferation known to be induced by isotretinoin.     

The microbial colonization of inflamed acne vulgaris lesions

Seventy one papules in the early stages of inflammatory development were isolated from acne vulgaris affected skin and their content of micro-organisms characterized. The progress of lesions prior to excision was monitored by tracing an area of the upper back onto a transparent acetate sheet. This template was used the next day, and in some cases after 3 days, to identify inflamed lesions of less than 1 day and 2-3 days duration. These were biopsied, and pilosebaceous units isolated by micro-dissection, homogenized and microbial populations studied by viable counting and microscopy. Propionibacteria colonised 68% of '1 day' duration lesions and 79% of '3 day' duration lesions; staphylococci colonized 19% and 32% respectively and Pityrosporum spp. (Malassezia furfur) were found in 52% and 68%. Although the prevalence of each microbial group was higher in the more chronic lesions, these differences were not statistically significant. The microbial profile of inflamed lesions was similar both qualitatively and quantitatively to non-inflamed lesions studied previously. These results call into question the role of micro-organisms as the initiators of inflammation in acne vulgaris.