Pigmentary Problems in the Tropics

Antityrosinase and antimicrobial activities from Thai medicinal plants

Various dermatological disorders and microbial skin infection can cause hyperpigmentation. Therefore, screenings for whitening and antimicrobial agents from Thai medicinal plants have been of research interest. Seventy-seven ethanol plant extracts were investigated for antityrosinase activity, eleven samples showed the tyrosinase inhibition more than 50 % were further preliminary screening for antimicrobial activity by agar disc diffusion and broth micro-dilution methods. Artocarpus integer (Thunb.) Merr. (Moraceae) root extract, which showed the potential of tyrosinase inhibition with 90.57 ± 2.93 % and antimicrobial activity against Staphylococcus aureus, S. epidermidis, Propionibacterium acnes and Trichophyton mentagophytes with inhibition zone as 9.10 ± 0.00, 10.67 ± 0.09, 15.25 ± 0.05 and 6.60 ± 0.17 mm, respectively was selected for phytochemical investigation. Three pure compounds were isolated as artocarpin, cudraflavone C and artocarpanone. And artocarpanone exhibited anti-tyrosinase effect; artocarpin and cudraflavone C also showed the potential of antibacterial activity against S. aureus, S. epidermidis and P. acnes with MIC at 2, 4 and 2 μg/ml, respectively and MBC at 32 μg/ml for these bacteria. So, these pure compounds are interesting for further study in order to provide possibilities of new whitening and antibacterial development. This will be the first report of phytochemical investigation of A. integer root.

Estudo comparativo morfofuncional de melanócitos em lesões de melasma

FUNDAMENTOS - Melasma é hipermelanose comum caracterizada por máculas acastanhadas em áreas fotoexpostas, cuja fisiopatogenia não é totalmente esclarecida. OBJETIVOS - Caracterizar e comparar morfologica e funcionalmente os melanócitos da epiderme sã com os da pele afetada por melasma. MÉTODOS - Avaliaram-se 12 pacientes portadores de melasma facial, sendo realizadas biópsias da pele lesada e pele sã adjacente. Os cortes foram corados por hematoxilina-eosina, Fontana-Masson, marcados pelo Melan-A e submetidos à microscopia eletrônica. A quantificação epidérmica de melanina e melanócitos foi estimada a partir de análise citomorfométrica digital. RESULTADOS - Todas as pacientes eram mulheres com média de idade 41,3±2,8 anos. Ao Fontana-Masson evidenciou-se importante aumento da melanina epidérmica na pele lesada em relação à pele sã. A marcação pelo Melan-A demonstrou melanócitos maiores com dendritos proeminentes na pele lesada. Observou-se maior densidade de melanina epidérmica na pele lesada, e a análise digital do número de melanócitos da epiderme não demonstrou diferença significativa entre pele lesada e sã. À microscopia eletrônica, observaram-se número aumentado de melanossomas maduros nos ceratinócitos e melanócitos com organelas citoplasmáticas proeminentes na pele lesada. CONCLUSÕES - Melanogênese aumentada na epiderme com melasma em relação à epiderme normal adjacente.

Immunopathologic study of erythema dyschromicum perstans (ashy dermatosis)

Erythema dyschromicum perstans (EDP) is a pigmentary disease of unknown etiology in which damage to basal cells is thought to be mediated by adhesion molecules. The aim of this study was to characterize the histopathology and immunopathology of EDP. Forty-three patients from Medellín, Colombia, with the diagnosis of EDP were evaluated. Skin biopsy specimens were obtained for histopathology and immunohistochemistry, using monoclonal antibodies directed against the following markers: CD4, CD8, CD56, CD1a, CD68, CLA, HLA-DR, ICAM-1 and LFA-1alpha. A dermal lymphocytic infiltrate was observed in all cases, with a perivascular location in 86%. Other histologic features included melanophages in all specimens, vacuolization of the basement membrane zone (BMZ) 58% and exocytosis of lymphocytes (53.5%). The mean number of total leukocytes was 1510 cells mm-2 of tissue. There was a predominance of CD8+ T lymphocytes in the dermis and HLA-DR+, ICAM-1+ keratinocytes in the epidermis. Exocytosis of cutaneous lymphocyte antigen (CLA)+cells was observed in areas of BMZ damage, suggesting that response to antigenic stimulation may play a role in the development of EDP.

HLA-DR association with the genetic susceptibility to develop ashy dermatosis in Mexican Mestizo patients

BACKGROUND

Ashy dermatosis, also known as erythema dyschromicum perstans, is an acquired benign disease, characterized by blue-gray pigment patches with erythematous borders. The cause is still unclear, but probably has an immunologic basis.

OBJECTIVE

The aim of this study was to determine gene frequencies of the HLA-DR alleles in Mexican patients with ashy dermatosis and compare them with ethnically matched healthy control subjects to reveal the genetic susceptibility to develop ashy dermatosis.

METHODS

We included 23 consecutive patients with clinical and histopathologic confirmed diagnosis of erythema dyschromicum perstans. Patients and control subjects received a questionnaire to determine their ethnic origin and a peripheral blood sample was taken for DNA extraction. Finally, Genetic HLA-DRB1 was performed by polymerase chain reaction sequence-specific oligonucleotide reverse dot blot hybridization.

RESULTS

Of the 23 patients included in this study, 65% were women and 35% were men. We observed that the disease was located in the trunk in 17 patients (74%) and the upper limbs in 15 patients (65%). The most frequent allele was HLA-DR4 (65%) (pC < 1 x 10(-6), odds ratio = 6.0, 95% confidence interval = 2.8-12.7) whereas in control subjects it was 23%. The most frequent molecular subtype in both patients and healthy control subjects was DRB1( *)0407, being statistically significant after comparing the two groups (pC < 1 x 10(-6), odds ratio = 7.0, 95% confidence interval = 3.1-15.8).

LIMITATIONS

Since this is a disease strongly influenced by ethnicity, extrapolation to other ethnic groups is limited.

CONCLUSIONS

Many factors influence the ethiopathogenesis of erythema dyschromicum perstans, but it is strongly suggested to have an important genetic susceptibility conferred by genes located within the major histocompatibility complex region.

Association of HLA loci alleles and antigens in Saudi patients with vitiligo

HLA complex is composed of several closely linked loci, each containing several alleles, yielding a high expression of polymorphism. Vitiligo, a commonly acquired dermatological disorder, has been associated with different HLA antigens in different ethnic groups. In this study, HLA classes I (HLA-A, B, and C) and II (HLA-DR, DQ) antigens/alleles were analyzed in a group of 80 Saudi subjects consisting of vitiligo patients (40) and matched controls (40). The frequency of antigens of various HLA loci was tested using two-stage microcytotoxicity assays, while the frequency of alleles of HLA-DR was screened by polymerase chain reaction/sequence specific primers (PCR/SSP) method. The frequencies of HLA-B7, B15, Bw6, Cw6, Cw7, and DRB4*010101 were found to be significantly higher in vitiligo patients compared to controls [P = 0.029, 0.015, 0.033, 0.009, 0.043, and 0.015, respectively, with relative risk (RR) > or = 3, etiologic fraction (EF) > or = 0.4]. On the other hand, HLA-A9, B5, DQ1, and DRB3*010101 were significantly decreased in vitiligo patients compared to healthy Saudis [P = 0.008, 0.004, 0.028, and 0.04, respectively, with RR < 1 and preventive fraction (PF) < 0.5]. Among the patients, the highest allele frequency was noted for DRB4*010101(70%), while in controls it was for DRB3*010101 (72.5%). These results for antigens and allele frequency of various HLA Loci in vitiligo patients and control subjects suggested that HLA-B7, Bw6, Cw6, Cw7, and DRB4*010101 could be susceptible to vitiligo, while HLA-A9, B5, DQ1, and DRB3*010101 might be negatively associated with the development of vitiligo in Saudis.

Coexistence of pityriasis versicolor and erythrasma. Fallbericht. Pityriasis versicolor vergesellschaftet mit Erythrasma

We describe a 53-year-old woman with pityriasis versicolor together with erythrasma that was localized in the axillary and genitocrural region. The coexistence of these infections is rare and we propose the use of methylene blue stain for the diagnosis of both diseases.

Erythema dyschromicum perstans: Response to dapsone therapy

Erythema dyschromicum perstans (EDP) is a rare disorder characterized by asymptomatic, slowly progressive, ash-gray macular pigmentation of the skin, which usually occurs from age 5 years through adult life. Most cases reported to date are of Latin American and Indian patients. Rare cases have been reported from Turkey. No treatment of choice is presently available. Various therapies have been tried, including sun protection, chemical peels, antibiotics, corticosteroids, vitamins, isoniazid, griseofulvin, and chloroquine, without any benefit. Some authors have suggested the therapeutic efficacy of clofazimine and dapsone on EDP. We report a case of EDP that responded remarkably well to treatment with dapsone.

Erythema dyschromicum perstans in prepubertal children

Erythema dyschromicum perstans (EDP) is a rare disorder of pigmentation that is most common in Hispanic patients. In adults, EDP has a slow onset and is unlikely to resolve spontaneously. The etiology and clinical course in children is poorly defined. Physical examinations, chart reviews, and telephone interviews were performed for eight pediatric patients with EDP who were followed at Children's Memorial Hospital in Chicago between 1990 and 1998. All the patients available for long-term follow-up (five of the eight) experienced complete clearance without recurrence in an average of 2.5 years. In all of our patients, the onset was noted from July to December. The administration of aminopenicillins was coincident with the development of EDP in two of the patients. Review of the English-language literature reveals that 25 prepubertal children have previously been reported. Including our patients, 69% of prepubertal children with EDP experienced resolution. We concluded that the clinical course of childhood (prepubertal) EDP differs from that of adult EDP, and it is more likely to resolve within 2-3 years.

Unusual leukoderma after erythema multiforme: a case report

Erythema multiforme is an inflammatory disorder of the skin that usually fades without sequelae. It is well known that after inflammatory events, hyper- or hypochromic spots can remain, especially in skin types III-VI, but achromia is very rare. We report a case of residual leukoderma after erythema multiforme.

Disorders of hyperpigmentation

Hyperpigmentation is a common disorder of the skin, particularly in brown-skinned patients. Melasma is a common cause of facial hyperpigmentation and can be resistant to treatment. A combination of topical creams and gels, chemical peels, and sunscreens may be necessary for significant improvement. Erythema dyschromicum perstans is a dermal pigmentation seen on the trunk and proximal extremities, most commonly presenting in dark-skinned Hispanics. Drug-induced and postinflammatory hyperpigmentation may last for many months after the offending drug or dermatitis has been eliminated. These disorders, including their management, is reviewed in this article.

Primary macular amyloidosis: an ultrastructural approach to diagnosis

Seven cases of primary macular amyloidosis were studied on skin biopsies. The Congo red stain was positive only in three cases, whereas the ultrastructural observation allowed for the detection of amyloid deposits in all biopsies. Fibrillary degeneration of basal keratynocytes was occasionally observed, and regressive changes of keratynocytes and dermal nerve bundles presumably related to the intensity of the scratch trauma were detected in one case. In six biopsies mast cell profiles exhibiting various degrees of degranulation were detected in the dermis. Melanosome aggregates were also observed consistently in dermal macrophages and occasionally in Schwann cells. A variable degree of structural alteration was observed in dermal unmyelinated nerve fibers. Even if the intimate mechanism of amyloid deposition was not explained by the ultrastructural study, this approach is a useful instrument in the differential diagnosis of cutaneous macular hyperpigmented lesions.

Skin problems in the traveler

Skin lesions are common in travelers and include a mix of mundane dermatologic problems and rare diseases acquired only in remote or tropical regions. The morphology, distribution, and progression of the lesions are useful in assessing possible causes. Early in the evaluation it is important to determine whether the patient might have a process that is rapidly progressive, treatable, or transmissible. In addition to routine laboratory studies, biopsy and serologic tests are often necessary to confirm a specific diagnosis.

Lichen planus pigmentosus presenting in zosteriform pattern

Lichen planus pigmentosus (LPP) has thus far been described as a condition of unknown etiology which clinically differs from the classical lichen planus (LP) by exhibiting dark brown macules and/or papules mostly in exposed areas and flexural folds and a longer clinical course without pruritus or scalp, nail or mucosal involvement. Histopathologically, LPP shows the typical changes seen in LP, but with thinning of epidermis. We report a case of LPP that developed in a unilateral, zosteriform pattern on the left flank of a 49-year-old man. This case seems to lie in the middle of the spectrum between classical LP and ashy dermatosis, and, to the best of our knowledge, is the first report of LPP presenting in the zosteriform pattern.

Vitiligo

Vitiligo involves a progressive loss of melanocytes from the epidermis and hair follicles. Milky-white patches appear resulting in cosmetic disfiguration that is most apparent in dark-skinned individuals. The disease is further classified according to distribution pattern and extent of depigmentation. The presence of several clinical subtypes may reflect the diversity in causative factors. To select appropriate therapeutic measures it is important to distinguish vitiligo from other disorders that affect melanocyte function. Although vitiligo has a characteristic clinical appearance and histological features, the presence of early or atypical lesions often requires the exclusion of other disorders such as postinflammatory hypopigmentation and piebaldism. Multiple hypotheses have been put forward to explain vitiligo. An inherited tendency to develop depigmentation may involve the inherent aberrancies that have been observed in nonlesional vitiligo melanocytes in vivo as well as in vitro. These abnormalities potentially render vitiliginous melanocytes more vulnerable to assaults from extracellular factors. Such factors include keratinocyte physiology, extracellular matrix composition, humoral and cellular immunity, and environmental agents. Therapies aimed at repopulation of lesional skin include phototherapy, application of topical corticosteroids, and transplantation of skin or skin cells. Moreover, micropigmentation or camouflage can be used to restore a pigmented appearance to lesional skin. In patients in which vitiligo affects extensive areas of the body, depigmentation may be the treatment of choice. In all, this acquired pigmentary disorder can be treated in a variety of ways and should not be regarded as an untreatable affliction.