Hidradenitis Suppurativa: An Asian Perspective from a Singaporean Institute

Background

Demographic studies of hidradenitis suppurativa (HS) in Western countries have found an association with the female gender and with co-morbidities, such as the metabolic syndrome. There are few studies in an Asian context.

Objective

This study examines the characteristics of HS at a Singaporean institute and compares them to those of existing studies in the West.

Methods

We report a series of 58 patients with HS seen at the University Dermatological Clinic, National University Hospital, Singapore, over a 13-year period between January 2004 and December 2016.

Results

Of 58 patients, 34 were male (58.6%). The axilla was the most common site affected, followed by the groin and buttocks. We did not find significant differences in disease characteristics between males and females, such as disease severity or location of disease. Metabolic co-morbidities were common, although paediatric-onset HS patients were less likely to be overweight, obese or smokers.

Conclusion

The higher proportion of male HS patients in our cohort compared to the West may reflect differences in the prevalence of obesity and smoking in the 2 populations. Metabolic co-morbidities were similarly prevalent in both adult and paediatric HS patients. These findings offer insight into the factors influencing the development of HS.

Isolated Actinic Lichen Planus of the Lower Lip

Oral lichen planus (LP) is a common manifestation in patients with LP; however, isolated lip LP is rare and may mimic other conditions such as lichenoid drug eruptions, actinic cheilitis, and early carcinoma in situ in the absence of typical skin lesions. Actinic lichen planus (ALP) is a variant of LP occurring on light-exposed areas in patients with dark skin. We report the case of a Chinese female with isolated ALP of the lower lip, mimicking herpes simplex infection at presentation. The presence of prognathism, involvement of the lower lip, and flares associated with sunlight reinforces the role of sun exposure in the development of this condition.

Guidelines for the Management of Atopic Dermatitis in Singapore

INTRODUCTION

Atopic dermatitis is a common, chronic pruritic condition affecting both children and adults, which has a negative impact on the quality of life. These guidelines were developed by an expert workgroup appointed by the Dermatological Society of Singapore, to provide doctors with information to assist in the management of their patients with atopic dermatitis. The workgroup members are experienced dermatologists with interest and expertise in eczemas.

MATERIALS AND METHODS

Workgroup members arrived at a consensus on the topics to be included. Relevant studies from the literature were assessed for best evidence, supplemented by the collective experience of the workgroup.

RESULTS

For mild atopic dermatitis, emollients, mild potency topical steroids and topical calcineurin inhibitors are recommended. For moderate-to-severe atopic dermatitis, the use of emollients, moderate-to-potent topical steroids, topical calcineurin inhibitors, wet dressings, antimicrobials for secondary skin infection, phototherapy, and systemic therapy (e.g. prednisolone, cyclosporine, azathioprine or methotrexate) may be warranted. Patients with moderate-to-severe atopic dermatitis should be managed in conjunction with a dermatologist.

CONCLUSION

Good outcomes can be achieved with an individualised therapeutic approach combined with adequate patient and parental education.

A Fatal Case of "Bullous Erysipelas-like" Pseudomonas Vasculitis

Erysipelas is a generally benign superficial bacterial skin infection, and its bullous form constitutes a rare and more severe variant. We describe the first and fatal case of “bullous erysipelas-like” septic vasculitis due to Pseudomonas bacteremi. A 69-year-old Chinese man presenting with diarrhea and septic shock initially began to rapidly develop sharply defined erythematous plaques with non-hemorrhagic bullae over his lower limbs. Culture of the aspirate from the bullae was positive for Pseudomonas aeruginosa. This was also consistent with his blood cultures showing Pseudomonas bacteremia. Histology of the skin lesion showed microthrombi and neutrophilic infiltrates in blood vessels with Gram-negative bacilli extruding from the vessel walls, characteristic of septic vasculitis. The bullous erysipelas-like lesions seen in this patient represents a rare manifestation of both septic vasculitis and Pseudomonas infection.

Retrospective Study on Autoimmune Blistering Disease in Paediatric Patients

BACKGROUND

Autoimmune blistering diseases (AIBDs) are rare in children and their prevalence in Singapore is unclear. We aimed to investigate the clinical and immunopathologic characteristics of children diagnosed with AIBDs in Singapore.

MATERIALS AND METHODS

The clinical and histology databases at the National Skin Centre in Singapore were searched to identify patients younger than 18 years old diagnosed with an AIBD from January 1, 1998, through December 31, 2012. Patient demographic characteristics, presentation, triggers, investigations, treatments, and disease course were analyzed.

RESULTS

Twelve patients with AIBDs were identified; five (41.7%) had linear immunoglobulin A disease (LAD); two (16.7%) each had pemphigus vulgaris (PV), bullous pemphigoid, and bullous systemic lupus erythematosus; and one (8.3%) had pemphigus foliaceus. Four (33.3%) were female and eight (66.7%) male. The mean age of onset was 8.7 years (range 2-17 years). Most patients were treated with steroids and adjuvant immunosuppressants. Intravenous rituximab was used effectively in a patient with recalcitrant PV. The mean follow-up was 2.35 years (range 0.17-7.33 years). As of the last follow-up, four (33.3%) patients were in complete remission off therapy, two (16.7%) were in complete remission on therapy, four (33.3%) were in partial remission on therapy, and two (16.7%) were lost to follow-up.

CONCLUSION

Consistent with the existing literature, our study shows that LAD is the most common cause of AIBDs in children. Although common in the West, dermatitis herpetiformis was not identified in the current study. Intravenous rituximab may be considered in recalcitrant childhood PV, but vigilant monitoring for side effects is crucial. Immunohistopathologic evaluation is important and repeat biopsies may be of value in patients with atypical disease courses.

Lichen nitidus presenting with nail changes--case report and review of the literature

Lichen nitidus of the nail is rare and can precede the onset of skin lesions. Delayed diagnosis is common. We present an unusual case of lichen nitidus-associated nail changes that preceded the onset of skin lesions in a 4-year-old Indian girl. We also conduct a review of six other cases of lichen nitidus with nail involvement from the English-language literature. Clues to the diagnosis of lichen nitidus include violaceous or pigmentary changes of the nail fold and subtle lichenoid papules on the affected digits. Lichen nitidus of the nails appears to be less severe than nail changes of lichen planus and is generally self-limiting. Understanding the natural history of lichen nitidus of the nails will help physicians better counsel patients and their families.

Trichotillomania in Children

BACKGROUND

Trichotillomania is an often underdiagnosed condition. Little is known about trichotillomania in childhood. We aimed to analyze the characteristics of children with trichotillomania to increase information on this condition.

METHODS

A retrospective study of an electronic database was performed in a tertiary children's hospital. Information from patients with trichotillomania was systematically classified under the categories 'who', 'what', 'when', 'where', 'why', and 'how'.

RESULTS

A total of 33 patients had a diagnosis of trichotillomania (28 females, 5 males; peak age between 3 and 4 years). Scalp involvement was most common and nail biting was observed in 5 patients. Only 51.5% of patients had parents who noticed their child's hairpulling. Hair on or under the bed was the most common clue suggesting that hairpulling occurred. Triggering factors identified in 16 children included physical appearance, family-related issues, school-related issues, and concurrent illness. The noninvasive hair pull test was negative in all children. There was a high non-follow-up rate, and treatment outcomes varied.

CONCLUSION

A set of 6 specific questions, based on the '5Ws and 1H' principle, facilitates the gathering of important information on children with unexplained nonscarring hair loss and helps clinicians be cognizant of possible outcomes of trichotillomania. This will be especially useful to clinicians who are not familiar with this elusive condition.

Complementary role of a polymerase chain reaction test in the diagnosis of onychomycosis

BACKGROUND

The successful treatment of onychomycosis depends on accurate diagnosis. Conventional diagnostic methods, including direct microscopy and fungal culture, are non-specific, insensitive and time-consuming. Recently, PCR has shown promise in improving the diagnosis of onychomycosis. We aimed to evaluate a commercially available PCR kit for the in vitro detection of dermatophytes and specifically Trichophyton rubrum in nail specimens with suspected onychomycosis, and to compare the detection rates of PCR with conventional diagnostic methods.

METHODS

Nail specimens were prospectively collected from patients with clinically suspected onychomycosis. All nail specimens were positive on direct microscopic examination. PCR and fungal cultures were administered, and the detection rates of dermatophytes were compared.

RESULTS

 In all, 107 nail specimens were analysed. The fungal culture was positive in 57 (53%) specimens (38 dermatophytes and 19 non-dermatophytes). PCR was positive in 77 (72%) specimens (63 T. rubrum and 14 pan-dermatophyte). A total of 37 specimens (35%) were positive for both fungal culture and PCR. PCR detected dermatophytes in 39 specimens that were missed by the fungal culture, increasing the diagnosis of dermatophyte-positive specimens by 37%. Five dermatophyte-culture-positive specimens were negative for PCR.

CONCLUSIONS

This study demonstrates that PCR increases the sensitivity of detection of dermatophytes in nail specimens. Despite its limitations, the use of PCR can complement direct microscopic examination and fungal cultures to aid clinicians in the diagnosis of suspected dermatophytic onychomycosis.

Case of primary localized cutaneous amyloidosis with protean clinical manifestations: lichen, poikiloderma-like, dyschromic and bullous variants

Primary localized cutaneous amyloidosis (PLCA) commonly presents as macular and lichen variants. We present a case of a 27-year-old Chinese woman with cutaneous features of the rarely reported poikiloderma-like, dyschromic and bullous forms of PLCA, and the commoner lichen variant. There were no syndromic associations or systemic involvement, and the various morphological subtypes occurred in isolation from one another. We review the clinical spectrum of PLCA, highlight its protean clinical manifestations in this patient, and discuss its postulated pathogenesis in relation to its histopathological features.

A dramatic response to a single dose of infliximab as rescue therapy in acute generalized pustular psoriasis of von Zumbusch associated with a neutrophilic cholangitis

Generalized pustular psoriasis of von Zumbusch is an unstable, inflammatory form of psoriasis, with the hallmark of neutrophil infiltration in cutaneous as well as extracutaneous lesions. It is often recalcitrant, making treatment difficult. Tumour necrosis factor-alpha antagonists including infliximab have been used with success in treating recalcitrant cases. We report a case of a 48-year-old Chinese female patient with a long-standing history of poorly controlled generalized pustular psoriasis which was resistant to multiple therapies. During a severe flare, a single dose of infliximab resulted in rapid clearing of cutaneous lesions, together with resolution of liver function abnormalities that are likely secondary to neutrophilic cholangitis. Subsequent maintenance therapy with acitretin allowed remission of pustular disease for 7 months. This demonstrates the efficacy of single-dose infliximab for both cutaneous lesions and systemic hepatic involvement in generalized pustular psoriasis.