Hiok-Hee Tan

Viral infections affecting the skin in organ transplant recipients: epidemiology and current management strategies.

Viral skin infections are common findings in organ transplant recipients. The most important etiological agents are the group of human herpesviruses (HHV), human papillomaviruses (HPV), and molluscum contagiosum virus. HHV that are important in this group of patients are herpes simplex virus (HSV) types 1 and 2, varicella-zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), HHV-6 and -7, and HHV-8, which causes Kaposi sarcoma (KS). HSV infections are characterized by their ability to establish latency and then reactivate at a later date. The most common manifestations of HSV infection in organ transplant recipients are mucocutaneous lesions of the oropharynx or genital regions. Treatment is usually with acyclovir, valaciclovir, or famciclovir. Acyclovir resistance may arise although the majority of acyclovir-resistant strains have been isolated from AIDS patients and not organ transplant recipients. In such cases, alternatives such as foscarnet, cidofovir, or trifluridine may have to be considered. VZV causes chickenpox as well as herpes zoster. In organ transplant recipients, recurrent herpes zoster can occur. Acute chickenpox in organ transplant patients should be treated with intravenous acyclovir. CMV infection occurs in 20–60% of all transplant recipients. Cutaneous manifestations, which include nonspecific macular rashes, ulcers, purpuric eruptions, and vesiculobullous lesions, are seen in 10–20% of patients with systemic infection and signify a poor prognosis. The present gold standard for treatment is ganciclovir, but newer drugs such as valganciclovir appear promising. EBV is responsible for some cases of post-transplant lymphoproliferative disorder, which represents the greatest risk of serious EBV disease in transplant recipients. HHV-6 and HHV-7 are two relatively newly discovered viruses and, at present, the body of information concerning these two agents is still fairly limited. KS is caused by HHV-8, which is the most recently discovered lymphotrophic HHV. Iatrogenic KS is seen in solid-organ transplant recipients, with a prevalence of 0.5–5% depending on the patient’s country of origin. HPV is ubiquitous, and organ transplant recipients may never totally clear HPV infections, which are the most frequently recurring infections in renal transplant recipients. HPV infection in transplant recipients is important because of its link to the development of certain skin cancers, in particular, squamous cell carcinoma. Regular surveillance, sun avoidance, and patient education are important aspects of the management strategy.

Antibacterial therapy for acne: a guide to selection and use of systemic agents.

Acne vulgaris is a very common disorder, affecting virtually every adolescent at some point in time. Systemic antibacterials have been used in the treatment of acne for many years, and there are several commonly used antibacterials which have established efficacy and safety records. In recent years, the issue of antibacterials resistance has become more prominent, especially with concerns that Propionibacterium acnes can transfer antibacterials resistance to other bacteria within the resident skin flora.Commonly used antibacterials include tetracycline, doxycycline, minocycline, erythromycin (and other macrolides) and trimethoprim/sulfamethoxazole (cotrimoxazole). The choice of antibacterial should take into account efficacy, cost-effectiveness, benefit-risk ratios, patient acceptability and the potential for the development of resistance.Poor clinical response can be the result of poor compliance, inadequate duration of therapy, development of gram-negative folliculitis, resistance of P. acnes to the antibacterial(s) administered, or a high sebum excretion rate.In order to help prevent the development of resistance a number of measures should be undertaken: antibacterials are prescribed for an average of 6 months; if retreatment is required, utilize the same antibacterial; generally, antibacterials should be given for at least 2 months before considering switching due to poor therapeutic response; concomitant use of oral and topical chemically-dissimilar antibacterials should be avoided (try benzoyl peroxide and/or retinoids instead) and systemic isotretinoin should be considered if several antibacterials have been tried without success.

Topical Antibacterial Treatments for Acne Vulgaris

AbstractTopical antibacterial agents are an essential part of the armamentarium for treating acne vulgaris. They are indicated for mild-to-moderate acne, and are a useful alternative for patients who cannot take systemic antibacterials. Topical antibacterials such as clindamycin, erythromycin, and tetracycline are bacteriostatic for Propionibacterium acnes, and have also been demonstrated to have anti-inflammatory activities through inhibition of lipase production by P. acnes, as well as inhibition of leukocyte chemotaxis. Benzoyl peroxide is a non-antibiotic antibacterial agent that is bactericidal against P. acnes and has the distinct advantage that thus far, no resistance has been detected against it. Combined agents such as erythromycin/zinc, erythromycin/tretinoin, erythromycin/isotretinoin, erythromycin/benzoyl peroxide, and clindamycin/benzoyl peroxide are increasingly being used and have been proven to be effective. They generally demonstrate good overall tolerability and are useful in reducing the development of antibacterial resistance in P. acnes. The selection of a topical antibacterial agent should be tailored for specific patients by choosing an agent that matches the patient’s skin characteristics and acne type. Topical antibacterial agents should generally not be used for extended periods beyond 3 months, and topical antibacterials should ideally not be combined with systemic antibacterial therapy for acne; in particular, the use of topical and systemic antibacterials is to be avoided as far as possible.

Cutaneous sarcoidosis in Asians: a report of 25 patients from Singapore

Sarcoidosis is a systemic noncaseating granulomatous disorder of unknown origin involving multiple organ systems. There has been no report so far to describe the epidemiological pattern of cutaneous involvement in sarcoidosis in South‐East Asia with diverse ethnic groups. A retrospective study examining the clinicopathological features of all patients diagnosed with sarcoidosis at a tertiary dermatology centre in Singapore from 1980 to 2003 was conducted. Cutaneous sarcoidosis was diagnosed in 25 patients: 13 were Indian, 11 were Chinese and one was Eurasian. Cutaneous manifestations included papules, nodules, plaques and scarring alopecia. Extracutaneous involvement of lymph nodes (four patients), lungs (eight patients) and eyes (two patients) was seen. Eight patients had abnormal chest radiographic findings. Histopathological examination of skin lesions revealed noncaseating, epithelioid granulomatous infiltration in the dermis without evidence of mycobacterial infection, deep fungal infection or polarizable birefringent material. Treatment modalities included corticosteroids, hydroxychloroquine, isotretinoin, methotrexate and surgical excision. Five patients had complete resolution of the cutaneous lesions. Cutaneous sarcoidosis is rare in Asia and indeed in Singapore. Extracutaneous involvement is not uncommon and a thorough clinical evaluation should be undertaken.

Occupational skin disease in workers from the electronics industry in Singapore

Of 149 workers from the electronics industry with occupational dermatoses seen at the Joint Occupational Dermatoses Clinic at the National Skin Centre, Singapore, 51.0% (76) were diagnosed to have irritant contact dermatitis, 40.9% (61) had allergic contact dermatitis, and 8.1% (12) had noncontact dermatitis. More than half of the patients were younger than 30 years of age. Common irritants were soldering flux, oils and coolants, solvents, and acids/alkalis. The most common allergens were nickel and resins, followed by rubber chemicals and the constituents of flux. Of the noncontact dermatitis, 8 were caused by occupationally relevant exacerbation of endogenous eczema, whereas there was one case each of miliaria, frictional dermatitis, and fatal toxic epidermal necrolysis caused by trichloroethylene allergy.

Treatment of toxic epidermal necrolysis in AIDS with intravenous immunoglobulins

Summary Individuals with AIDS are at higher risk of developing severe cutaneous adverse drug reactions. We report two AIDS patients with drug‐induced toxic epidermal necrolysis (TEN). The suspected drugs were discontinued. Both patients were treated with intravenous human immunoglobulins at a dose of 1 g/kg body weight per day for two consecutive days and both experienced a good outcome. Intravenous immunoglobulin potentially lowers the morbidity and mortality of TEN and shortens the duration of the patients hospitalization.

Parasitic Skin Infections in the Elderly Recognition and Drug Treatment

There are many parasitic infections of medical importance, which can produce both systemic disease as well as skin lesions. For the most part, treatment of these infections in the elderly does not differ very much from that of younger patients. However, one must be aware that the geriatric population can present with certain challenges with regard to diagnosis of these diseases because history taking may be more difficult and patients often already have a set of other medical problems, which may overshadow the skin lesions. In addition, the clinical manifestations of these infections may not appear classical and may be altered. Dosages of drugs used to treat these infections, even topical agents, may require adjustments in this population. The recognition of scabies in elderly people living together is important and early treatment with topical scabiecides, including oral ivermectin, will help to control the spread of the infestation. Pediculosis may be a cause of pruritus in the elderly and can be treated with malathione, lindane or permethrin. Less common parasitic infections in the elderly, including cutaneous larva migrans and cutaneous leishmaniasis, present with a characteristic clinical picture and can be effectively treated with oral thiabendazole and intravenous antimonials.

Neurofibromatosis and reticulate acropigmentation of Dohi : A case report

Abstract: A 13‐year‐old boy had progressive pigmentary changes affecting his limbs which began when he was 9 months of age. He also had a history of café au lalt macules on his trunk since birth which were becoming more numerous. The diagnosis of reticulate acropigmentation of Dohi (dyschromatosis symmetrica hereditaria) and neurofibromatosis type 1 (NF‐1) was made on the basis of the clinical features. To our knowledge, this is the first report of these two conditions occurring in the same patient.

Doxycycline in the treatment of acne agminata

Clinically, a pedunculated appearance is extremely rare in metastatic malignant melanoma. In addition, the histopathological finding of melanoma cell epidermotropism is also rare in metastatic malignant melanoma. Here, we describe a case of epidermotropic metastatic malignant melanoma (EMMM) that showed a pedunculated appearance. A 71-year-old man presented with a 3-month history of an asymptomatic flesh-coloured tumour within his oral cavity. Physical examination revealed a dome shaped brown–red tumour in his oral cavity (Fig. 1a). Histopathological examination of this tumour revealed the growth of atypical melanocytes throughout the mucous epithelium and into the dermis to a depth of 3.4 mm, which led us to diagnose this tumour as a malignant melanoma (Fig. 1b). He also had a 2-month history of asymptomatic skin coloured tumours on his right shoulder and back. On his right shoulder, there was a pedunculated flesh-coloured scaly ovoid tumour 10 mm in diameter (Fig. 2a). Histological studies of this tumour showed various sized and shaped nests of melanoma cells that pushed aside collagen fibres and spread from the epidermis into the dermis (Fig. 2b-1). Within the epidermis, tumour nests were located mainly within the basal layer. Marked epidermotropism of the melanoma cells in the upper epidermis, demonstrating a Pagetoid cell appearance, could also be seen (Fig. 2b-2). On his back, there was an 8–9-mm sized,

A case of tuberculosis verrucosa cutis--undiagnosed for 44 years and resulting in fixed-flexion deformity of the arm.

Tuberculosis verrucosa cutis (TBVC) is a paucibacillary form of cutaneous tuberculosis caused by exogenous re‐infection in previously sensitized individuals. Here, we report an unusual case of TBVC in a 53‐year‐old Chinese woman that had been present for 44 years and resulted in fixed‐flexion deformity of her arm and functional disability. The diagnosis was made by a positive culture for Mycobacterium tuberculosis and she responded well to antituberculous therapy. To our knowledge, this is the first such case of TBVC reported in the English literature with sequelae of functional impairment of the arm.