A TB skin test ("Mantoux") can show if you have latent TB infection. You could have latent TB infection if you have ever spent time close to someone with active TB disease (even if you didn't know they were sick). Your health care provider will use a small needle to inject some harmless testing fluid (called "tuberculin") under the skin on your arm.
The test is "positive" if there is a bump of a certain size where the fluid was injected. This means you probably have TB germs in your body. Most people with a positive TB skin test have latent TB infection. To be sure, your doctor will examine you and give you a chest x-ray. You may need other tests to see if you have active TB disease.
Download I Have A Dry Patch Of Skin On My Arm
A person with vitiligo occasionally may have family members who also have the disease. Although there is no cure for vitiligo, treatments can be very effective at stopping the progression and reversing its effects, which may help skin tone appear more even.
Discuss your questions with your healthcare provider regarding which type of skin condition you have. You can have more than one skin condition at a time. Treatments for one may not work for the other.
The main symptom is brownish patches on the skin. These patches contain cells called mastocytes. When mastocytes release the chemical histamine, the patches develop into hive-like bumps. Younger children may develop a blister that is filled with fluid if the bump is scratched.
Many people first think they have spider bites. These infections commonly happen where skin has been cut or wounded, and on areas covered by hair (e.g., back of neck, groin, buttocks, armpit, beard area).
A specific type of eczema called nummular dermatitis causes a red rash and coin-shaped or oval patches on the skin. Nummular eczema and ringworm can appear very similar and be confused with each other because both cause a circular red rash and itchy skin.
Ringworm is a common term for a superficial fungal infection of the skin, which appears as scaly, red, round patches with a tendency to form rings. It is known as tinea corporis when it affects the body and tinea cruris when it affects the groin. Tinea capitis, or ringworm of the scalp, affects mainly children and can cause hair loss. However, this condition is relatively uncommon in Singapore. Healing may result in pigmentation of the skin.
This is a yeast infection that often affects moist areas like the skin folds, armpits and groin. It also occurs commonly on the genitalia and can cause a vaginal discharge in women. It is more common in people with diabetes mellitus and appears as itchy red spots or patches.
Apply antifungal cream to the affected areas two to three times a day for four weeks. Do not stop using the medication even when the rash has cleared. Continue using it for at least seven days after the infection appears to have cleared. In the case of white spots, the white colour remains even after the fungal skin infection has been successfully treated. However, this will gradually improve over time as the skin recovers its normal colour.
Seborrheic dermatitis is a common skin condition in the general population, but even more commonly found in people with PD. It causes patches of scaly, red skin and dandruff, primarily on the scalp and on the oily parts of the face such as the sides of the nose. In PD, it is thought to be caused by over-secretion of oils from the sebaceous glands in the skin. In much the same way that dysfunction of the autonomic nervous system (the nerves that control automatic body functions) cause non-motor symptoms in PD such as blood pressure dysregulation and urinary abnormalities, autonomic dysfunction of the nerves that control the oil glands of the face can cause seborrheic dermatitis.
Melanoma is a type of skin cancer consistently linked to PD. People who have had melanoma are at an increased risk for PD and people who have PD are at an increased risk of melanoma. Epidemiological studies have shown an increased risk of non-melanoma skin cancers in PD patients as well. Always be sure to talk to your doctor about any skin concerns.
A bald spot on your cat can vary in appearance, and your cat may have many areas of fur loss or just one or two. Depending on the cause, you may also notice that your cat has scabbing in places where they used to have fur. An external parasite, for example, can cause both hair loss as well as scabs on cats, as the parasite can damage both the hair follicle and the skin in general.
Cat owners should also be aware that some cats have naturally thinning hair, particularly on the tops of their heads or parts of their body they use to brush up against people and objects. This varies between breeds but is most noticeable in cats with dark fur and light skin. It is not usually an issue unless complete baldness occurs.
Functioning as the exterior interface of the human body with the environment, skin acts as a physical barrier to prevent the invasion of foreign pathogens while providing a home to the commensal microbiota. The harsh physical landscape of skin, particularly the desiccated, nutrient-poor, acidic environment, also contributes to the adversity that pathogens face when colonizing human skin. Despite this, the skin is colonized by a diverse microbiota. In this Review, we describe amplicon and shotgun metagenomic DNA sequencing studies that have been used to assess the taxonomic diversity of microorganisms that are associated with skin from the kingdom to the strain level. We discuss recent insights into skin microbial communities, including their composition in health and disease, the dynamics between species and interactions with the immune system, with a focus on Propionibacterium acnes, Staphylococcus epidermidis and Staphylococcus aureus.
Our skin is home to millions of bacteria, fungi and viruses that compose the skin microbiota. Similar to those in our gut, skin microorganisms have essential roles in the protection against invading pathogens, the education of our immune system and the breakdown of natural products1,2,3. As the largest organ of the human body, skin is colonized by beneficial microorganisms and serves as a physical barrier to prevent the invasion of pathogens. In circumstances where the barrier is broken or when the balance between commensals and pathogens is disturbed, skin disease or even systemic disease can result. Human skin sites can be categorized by their physiological characteristics, that is, whether they are sebaceous (oily), moist or dry (Box 1). Studying the composition of the microbiota at different sites is valuable for elucidating the aetiology of common skin disorders, which often have a preference for specific skin sites, such as eczema inside the elbow4 and psoriasis on the outside of the elbow5.
Most skin microbiome surveys have used amplicon sequencing. Over the past few years, however, major technical and analytical breakthroughs have enabled shotgun metagenomic sequencing studies. Figure 1 highlights the technical and procedural differences between amplicon and shotgun metagenomics and the different types of analyses that are possible with the data sets. As shotgun metagenomics does not sequence specific target regions, it simultaneously captures all genetic material in a sample, including human, bacterial, fungal, archaeal and viral, thus allowing relative kingdom abundances to be inferred, with the limitation that the DNA of different microorganisms may be differentially extracted depending on the sample preparation method14,15,16. Another advantage of shotgun metagenomic sequencing is that these data sets provide sufficient resolution to differentiate species and even strains within a species. This is crucial for identifying members of the Staphylococcus genus, which are difficult to classify to the species level with most amplicon sequencing approaches9. The ability to differentiate strains is important as more studies reveal the functional differences that exist between strains within a species17,18,19.
Through the use of longitudinal sampling, skin microbial communities were found to be largely stable over a 2-year study despite constant environmental changes25. Based on analyses at the strain and single-nucleotide level, this stability was determined by the maintenance of strains over time rather than the reacquisition of common species from the environment25. Similarly, in longitudinal surveys of the gut, specific species of an individual's microbiota have been found to persist for a year28 or more29. Bacterial and fungal communities at sebaceous sites were the most stable. Microbial communities of foot sites were the least stable, and eukaryotic DNA viruses varied the most over time25,26. The relative instability of foot microbial communities might be attributable to the transient presence of fungi in the environment.
Compared with the richer environment of our intestines, skin lacks many nutrients beyond basic proteins and lipids. To survive in such a cool, acidic and desiccated environment (Box 1), the resident microbiota of our skin have adapted to utilize the resources that are present in sweat, sebum and the stratum corneum1 (Table 1). For example, the facultative anaerobe P. acnes is able to thrive in the anoxic sebaceous gland by using proteases to liberate the amino acid arginine from skin proteins31 and lipases to degrade triglyceride lipids in sebum32; this releases free fatty acids, which promote bacterial adherence33,34,35. In facial samples, sebum levels of the cheek were shown to positively correlate with Propionibacterium spp. abundance36. Interestingly, for mammals such as mice, rats and dogs, which produce smaller quantities of triglyceride-rich sebum, P. acnes grows less well and is thus found at lower abundances37.
The lipids of sebum and the stratum corneum are also utilized by auxotrophic Malassezia and Corynebacterium species, as they are unable to produce their own lipids1. Corynebacterium spp. utilize these lipid compounds to generate the corynemycolic acids that coat their cell surface1. Consistent with the carbohydrate-deficient, lipid-rich environment of the skin, Malassezia spp. genomes are enriched for lipase genes and depleted for carbohydrate-utilizing enzyme genes compared with the genomes of other sequenced fungi38. Such differences may explain why Malassezia species predominate in the adult skin mycobiome. Finally, Staphylococcus spp. have evolved many strategies for surviving on the skin, including the ability to be halotolerant (that is, to withstand the high salt content of sweat) and utilize the urea that is present in sweat as a nitrogen source1. To further promote colonization, various Staphylococcus spp. can also produce adherens that promote attachment to the skin and proteases that liberate nutrients from the stratum corneum1. Overall, the skin harbours a heterogeneous community of microorganisms that each have distinct adaptations to survive on the skin. 2ff7e9595c
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