Investigations and dermatological tests.

Contents

Introduction

An experienced doctor can often diagnose a skin condition without the need for research. However, sometimes, skin swabs, scrapes and nail clippings, biopsies, and blood samples are sent to the laboratory, and allergy Evidence or images are organized. Research can also be used to monitor the effects of systemic deals.

Microbiology

Standard skin or wound swabs have a cotton tip on a plastic shaft and are generally placed in Amies gel routine means of transport bacterial cultureand, if applicable, antibiotic sensitivities.
Vaginal or male urethral swabs can be collected in a tampon to Polymerase chain reaction (PCR), a molecular biology technique used to detect chlamydia, gonorrhea, trichomoniasis, and others organisms.
Skin scrapings, nail clippings and removed hair are treated with potassium hydroxide (KOH) and examined directly microscopy before being planted for mushroom cultivation. An interim report can describe typical dermatophyte or yeast hyphae, arthrospores, and mycelia. Culture results and specific organisms identified are reported approximately 4 weeks later.
El medio de transporte viral se usa para detectar herpes simple y Herpes zoster por cultivo, immunofluorescence or PCR
Skin samples in a small amount of sterile saline can also be processed for Gram staining, microscopy, and culture, including low-temperature culture for atypical mycobacteria and identification of organisms such as leishmaniasis and deep fungi.

Histopathology

Most skin biopsy samples are sent to the laboratory in buffered formalin at 10%, with 24-hour fixation and processing time prior to histological examination by a histopathologist. The reports are issued in about a week. Interpreting skin biopsies requires considerable training and experience.
Samples for immunofluorescence must be placed in a culture medium, saline or liquid nitrogen and must be sent to the laboratory urgently.
The frozen sections have no fixative and can be seen immediately by a pathologist. In dermatology, are mainly used to determine whether a basal cell carcinoma has been completely surgically removed by Mohs surgery (microscopically controlled excision) Considerable skills and training are required to interpret frozen sections.
Cell cytology of the base of an ampoule can be evaluated on a tissue smear applied to a glass slide and fixed by air drying, ie Tzanck smears. It is fast but not very reliable for diagnosis.

Hematology

Neutrophilia is typical of infection but it can also accompany serious inflammatory disorders including generalized pustular psoriasis and neutrophilic skin disease like sweet syndrome or pyoderma gangrenous
Eosinophilia is associated with atopic eczemascabies bullous disease and lymphoma. It can be quite nonspecific in patients with erythroderma.
Lymphocytosis is associated with viral infections and certain bacterial infections like tuberculosis and syphilis.

Other blood tests

Renal, hepatic, thyroid and iron can be evaluated in patients with generalized disease pruritus, vasculitis or systemic symptoms.
Blood glucose and glycosylated hemoglobin detect and control diabetes, which may be relevant in infections or skin diseases associated with metabolic syndrome.
Anti-nuclear and removable nuclear antigen antibodies and tissue autoantibodies are evaluated in patients with suspicion connective tissue or autoimmune disease.
Proteins, including immunoglobulins, cryoproteins and complement, are evaluated in patients with vasculitis or connective tissue disease.
Specific serology requested for infections for example hepatitis B, hepatitis C, human immunodeficiency virus (HIV), syphilis.
Additional tests in vasculitis include anti-neutrophils cytoplasmic antibodies (HAUNCH), antiphospholipids and thrombophilia detection.
Hormonal tests are occasionally organized in women with acne, hirsutism, and androgenetics. alopecia if the symptoms indicate that these tests are justified, or if virilism is present.
Urinary and fecal or serum porphyrins are requested in patients who may have a cutaneous porphyria
Cytogenetics tests including karyotype, fluorescent in the place hybridization and comparative genomic hybridization.
Blood-based melanoma Screening tests (liquid biopsy) are being investigated.

Allergy tests

Determination of allergy requires careful history and examination, and testing must have a specific question in mind.

Puncture tests

Puncture tests for immediate hypersensitivity are not very helpful in investigating skin conditions. These tests are sometimes performed on patients with suspected contact. urticaria or latex allergy. They are not useful in atopics. dermatitis or acute/ /chronic spontaneous urticaria IgE tests have limited use in patients with type 1 hypersensitivity reactions

Patch tests

Patch tests are performed by specialized clinics for patients with suspected allergic contact dermatitis; They detect delayed hypersensitivity reactions. Patients must have chronic or recurring dermatitis.

A base common series Allergens and additional batteries of test substances are selected, depending on the site of eruption or occupational exposures.
Standardized allergen concentrations come from specialized companies.
The test patches are applied to the upper back on day 0, removed on day 2, and checked on day 4, and sometimes on day 7.
Photopatch tests require the application of a duplicate set of photoallergens, with exposure to Ultraviolet radiation to one of the allergen sets on the day of removal.
Interpreting misleading results can be challenging.
Atopia Patch tests are sometimes used in patients with atopic dermatitis with possible exacerbation by type 1 allergens, such as food or household dust Pinch.

Image

Radiological exams

X-rays, Connecticut scans, Magnetic resonance scans and ultrasound Tests are not routinely requested in dermatology, but can be arranged to detect systemic symptoms or to control treatment. They are essential to investigate advanced melanoma. See radiographic investigations in melanoma.

Wood Light Exam

Exposure to long wavelength UVA emitted by a Wooden lamp It is mainly used to investigate pigmentary disorders and chronic superficial skin infections such as pityriasis versicolor, where fluorescence supports a specific cause.

Digital dermoscopy

Digital dermoscopy is a digital image of skin lesions under dermoscopy. Ideally, these are accompanied by macroscopic and location images. Dermoscopic images can be taken using a variety of dermatoscopes, adapters, and video and still cameras using the contact and non-contact, polarized and non-polarized systems.

Mole mapping is a system in which the location of melanocytic naevi it is assigned to a mannequin, photographs of the entire body are taken, and macroscopic and digital images are recorded for lesions of clinical interest. The procedure is repeated at intervals to monitor patients at high risk for melanoma, particularly if they have many nevi or nevi with an unusual appearance.

Other

Optical coherence tomography and confocal reflectance microscopy are in vivo techniques for skin diagnoses. They are mainly used in research centers.

The future of dermatology includes smart tools to help diagnose skin lesions and rashes using artificial intelligence, convolutional neural networks, and other techniques.