Your dermatology internship starts tomorrow and you haven’t studied yet? No reason to panic! With these tips, you’ll easily survive the chief physician’s tests and you’ll learn how to make a skin finding – which is relevant not only for future dermatologists.
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Malignant Melanoma

Image: “Bösartiges Melanom” by Hans677. License: CC-BY-SA 4.0

Structure of the Skin

Before you start dealing with the subtleties of the study of efflorescences, it is recommended to revise the fundamental structure of the skin again.

The skin is the body’s largest organ, outermost covering of body and all parts of the body and consists of three big layers, which are close-knit to each other and have different functions: Epidermisdermis and subcutis.

Epidermis (upper skin)

The epidermis consist of a keratinized squamous epithelium, which is mainly formed by keratinocytes. Alongside the basal membrane, the melanocytes  to filter the ultraviolet radiation, can be found as well, which make the skin pigment as well as Langerhans-cells (immune cells) and Merkel cells. The basal layer holds the stem cells of the skin. The skin is renewed regularly, starting from the basal layer.

Its outermost covering is known as stratum corneum that protects the body from viruses, bacteria and other foreign bodies. Epidermis with other layers of skin protects the internal organs, muscles, blood vessels and nerves from injury.

The epidermis contains neither lymphatic nor blood vessels.

Structure of the Epidermis

Image: “Epidermis” by Blausen. License: CC BY 3.0

Dermis (corium)

The dermis is a layer of the skin that consists of connective tissue and is located between the epidermis and the subcutaneous fatty tissue.  It is thick layer formed by fibrous and elastic tissue. Next to the line between the epidermis and dermis is the dermo-epidermal junction, in which the basal membrane of the epidermis connects with the dermis. Rete ridges and anchoring fibrils ensure that under the impact of the shear forces, the epidermis does not detach from the dermis. Disruptions in this area can lead to typical blistering illnesses.

The dermis contains blood and lymphatic vessels, nerve fibres and sensory receptors (e.g. Meissner-corpuscles), hair, sweat and sebaceous glands. Their distribution is different in different parts of the body. For example , there are many hair follicles on the head but soles of feet don’t have them. Besides the fibroblasts, which produce the extracellular connective tissue, additional cells can be found in the dermis: tissue macrophages, lymphocytes, mast cells.

Dermal Circulation

Image: “Dermal Circulation” by BruceBlaus. License: CC BY 3.0


The connective and fatty tissue underneath the dermis serves the isolation and the mechanical protection of the skin. Fibrous tissue and elastic tissue provide flexibility and elasticity to the  skin.

Dermatological Diagnostics

Dermatology is primarily a visual field. The basis of dermatological diagnostics is the systematic and careful examination of the entire skin. This examination should take place in daylight.

Disorders have wide variation according geography, seasonal temperature change, humidity and environmental factors.

In case of an initial consultation no part of the skin should be skipped. That means that also the hands and soles, inframammary and the interdigital, inguinal, genital, axillary and perianal region should be examined as well the ears, adjacent mucous membrane like the lips, oral cavity, anus, conjunctivas and the nose, the skin appendages (hairs and nails) as well as the scalp should be checked.

Note: Pay attention to pigment changes which are suspicious of melanoma, skin tumors and in situ carcinoma during the examination.

In addition the overall skin condition should be assessed and described, concerning: complexion, condition, drought, turgor and smell.

Description of skin findings

The Texture, distribution and color of skin determine thdescription of skin ailments.The description of the anomalies of the skin found during examination are made with the assistance of the efflorescence gauge. The description of the efflorescences (Latin: “ex” = out, “florescere” = flower), the so called “flowers of the skin”, serves the uniform morphological description of skin abnormalities and is the basis for communication between dermatologists. Therefore the efflorescence gauge is a kind of “code”, which helps to describe nearly all of the pathological skin changes with just a few terms and modifications.

The efflorescences are divided into primary efflorescences, which arise on healthy, unchanged skin and are a direct consequence of the illness as well as into secondary efflorescences, which are the secondary change of a primary efflorescences.

Primary efflorescences

 Efflorescence Definition Example
Macula (spot)

Macula (Café au lait spot)

Image: “Macula (Café-au-lait-spot)” by Accrochoc. License: CC BY-SA 3.0

Outlined colour change, without increase of the substance. Different colours are possible.

Non-palpable, not raised or depressed relative to the skin

Red: increased circulation (erythema), bleeding in the skin (purpura)
blue: hematoma
white: lowered melanin, e.g. vitiligo
brown: increased melanin
Urticate (wheal)

Cold Urticaria

Image: “Urtica” by Templeton8012. License: CC BY-SA 3.0

Volatile protrusion of the skin, through exit of the serum Urticaria, mosquito bite, drugs, stings, autoimmunity
Papule (nodules)

Papule on the Nose

Image: “Papel” by M. Sand, D. Sand, C. Thrandorf, V. Paech, P. Altmeyer, F. G. Bechara. License: CC BY 2.0

Increase of the substance higher than the skin level, the diameter is smaller than 0,5 cm. it can be palpated or felt Lichen ruber, insect bites, seborrheic keratoses, warts skin cancers
Nodes (knot)

Schema Showing Nodes

Image: “Nodules” by Madhero88. License: CC BY-SA 3.0

Increase of the substance higher than the skin level, the diameter is bigger than 0,5 cm Skin tumor

Papule and Plaque

Image: “Papule and Plaque” by Madhero88. License: CC BY-SA 3.0

Flat sublimed increase of substance of the skin. Palpable, elevated or depressed lesions relative to skin Eczema, psoriasis
Bulla (blister) vesicle (bubbles)

Bulla and Vesicle

Image: “Vesikel und Bulla” by Madhero88. License: CC BY-SA 3.0

Cavity filled with liquid (e.g. serum, blood), possible in every layer of the three layers of the skin Pemphigus vulgaris, herpes simplex, burns, allergic contact dermatitis
Pustule (pustule)

Pustule on a Cheek

Image: “Teenager with Acne” by Diariodaj. License: Public domain

Cavity filled with pus, possible in every layer of the skin Folliculitis, acne, Psoriasis pustulosa

Secondary efflorescences

While the primary efflorescences occur on healthy skin, secondary efflorescences follow already present primary efflorescences.

 Efflorescence Definition  Example
 Squama (scale) Thickening of the horny layer (stratum corneum) of the epidermis, whitish sheds Psoriasis, tinea
Erosio (erosion) Superficial defect of the substance of the epidermis, healing without scars Pemphigus vulgaris, inflammatory diseases
Excoriation (artefact of scratching) Defect of the substance, which goes right through to the upper dermis. Scars are possible in case of healing of the defect Abrasions, itching illness of the skin
Crust (crust) Bearing of dried up secrete Serum, blood or pus out of smaller wound, infections,inflammatory diseases
Ulcer (ulceration) Defect of the substance which at least goes to the lower dermis, bad healing, scarring obligatory Ulcer cruris

Ulcus Cruris

Image: “Ulcus Cruris” by Redlinux. License: CC BY-SA 3.0 Venous stasis dermatitis, infections, vasculitis

Rhagade Crack shaped tears of brittle skin, in natural skin folds like the corner of the mouth and hands Hyperceratotic-rhagadiforme eczema of the hand, crack of the corner of the mouth
Cicatrix (scar) Wound closure with collagenous connective tissue after a deep defect of the substance. Possibly hypo- or hyper pigmented, caved-in, sublimed or the level of the skin Scar after ulcer or trauma

Scar after ulcer or trauma

Image: “Ulcus und Erosion” by Madhero88. License: CC BY-SA 3.0

Atrophy (skin thinning) Tissue loss in the area of multiple skin layers. Thinning of the epidermis and dermis Atrophy because of steroids or age, sun exposure, inflammatory diseases, neoplastic diseases
Lichenification Thickening of the skin with oversimplifying lichenification Atopic eczema

Description of the findings

The preparation of the dermatological finding should also always assess the overall clinical picture. A step by step approach can be helpful.

First, start with the description of the localization (area of the body) as well as the number of efflorescences (solitary, several or numerous herds). Based on this description it can be judged, whether it is a localized or a generalized phenomenon.

These terms can be helpful for closer description:

  • disseminated (sowed)
  • diffuse (fuzzy limited, extended)
  • generalized (disseminated over the whole body)
  • grouped (identical skin changes, lying directly next to each other)
  • confluent (passing into each other)
  • solitary (individually standing)
  • multiple
  • homogeneous
  • heterogeneous

Subsequently the separate herds need to be described morphologically. This includes the size and form, limitation, color, consistency and quality of the efflorescences. The expansion is measured if necessary and specified in length or by comparison.

In general, an efflorescence that is located more deeply has a sharper limitation. The color of inflammatory efflorescences can reveal its localization: In the upper dermis, the efflorescences are mostly sharply limited and bright red, in deeper layers the limitation is blurred and the color purple. With a spatula, made of glass, the reaction to pressure can be tested: Is the efflorescence movable? Does the color change under pressure?

Note: To assess efflorescences adequately, they have to be touched. It can be  helpful if you close your eyes.

The description of attendant symptoms like signs of inflammation (erythema, overheating), pain, pruritus (itching), exudation and burning completes the skin findings.


The anamnesis is used to clarify the development of the disease and is supposed to lead to a diagnosis, supported by previous findings and other relevant data. The anamnesis is the first important contact to the patients before they undress for examination. It is important to proceed gently and to turn from open, general questions to more “intimate” topics. Ask in a specific, unaggressive way. When in doubt, the relationship of trust between doctor and patient should not be compromised for the sake of a single question.

Important questions for the anamnesis

  • When exactly did the symptoms/skin changes start?
  • Where exactly did the skin changes start to appear?
  • Do the skin changes lead to subjective physical complaints? (pain, itching, hot/cold feeling)
  • What did the skin changes look like at first, did they change? How did they spread?
  • Do these complaints disturb their normal activities like sleep?
  • What did you do so far to treat your skin changes?
Note: Patients often understand terms like “blister”, “wheals”, “eczema” and similar terms in a differently than they are defined in dermatology . That is why it is important to ask the patient for their understanding of the different terms. Additional hints can be gathered through the questions according previous diseases of the skin/known illnesses, allergies, attendant symptoms like fever, weight loss and reduced general condition, previously consumed medicine, contact to noxious agents/chemical substances, habits and so on.

Questions towards the family’s anamnesis as well as journeys abroad can supply important insights. Las but not least the psychosocial situation of the patient as well as the personal impairments caused by the skin changes should be questioned.

Clinical Testing

Simple clinical tests can be conducted during the examination and can contribute important information for making a diagnosis. One of these simple tests, the previously mentioned palpation provides information about consistency, mobility, painfulness, soreness, heat or cold of the skin, pulsation and other characteristics of the efflorescence.

Crusts can be removed to assess the wound and the expansion of the wound. In case secrete is abstracted, it can also be assessed.

Furthermore there are specific clinical signs, which can give hints for certain characteristics of the skin or other illnesses.


Here the skin is irritated with a blunt object (e.g. a spatula made of wood) and the reaction is evaluated. The resulting reddish wheals normally disappear quite quickly. A red dermographism in contrast occurs after 15 seconds and is a sign of local vasodilatation (capillary dilatation), which leads to a significant redness in form of lines. A reflective vasodilatation (arterial dilatation) can produce a reflex erythema. This results in the formation linear wheals due to transudation of fluid. This is together known as triple response of Lewis.

dermographism with an urticarial origin can occur a few minutes after the red dermographism and possibly last for minutes. Because of a local release of histamine particularly by interaction of antigen with  IgE, it leads to swelling of the stretched patterns and itching.

The white dermographism (dermograhism albus), noticeable as a white stripe on the skin, is a sign of local vasoconstriction and is a hint for an atopic tendency, i.e. a tendency towards hypersensitive reactions like atopic dermatitis (neurodermatitisatopic eczema).

Dermographic urticaria resulting from pressure through clothing

Image: “Dermographic urticaria resulting from pressure through clothing.” by Openi. License: CC BY 3.0


Portrait of Heinrich Auspitz

Portrait of Heinrich Auspitz

Also known as the phenomenon of the bloody rope, serves the Auspitz-phenomenon, the diagnostic of a psoriasis. It can be defined by appearance of small isolated bleeding points on the surface of the skin after the removal of scales of psoriatic papule or plaque. If you scratch the scales of a psoriasis plaque with a spatula made of wood, the inflammatory dermis will appear underneath. If you scratch the exact same spot again with a wooden spatula, the dermis will be opened and a punctual bleeding, coming from the blood vessels of the papillary top will occur.

Technical Tools

To examine the skin various, sometimes simple tools are used in the field of dermatology. Besides the wooden spatula (which e.g. is used for triggering a dermographism), a spatula made of glass, magnifying glass and a dermatoscope are used. Additionally, the Wood-light (UVA-light), sonography, and histological procedures are used during the diagnostic.

Spatula made of glass (diascopy)

Diascopy of the cheek of a 57-year-old man treated with bosentan

Image: “Clinical appearance centrofacial telangiectasia (TAE) in patients treated with iloprost or bosentan after ten months. (b) diascopy of the cheek of a 57-year-old man treated with bosentan;” by Openi. License: CC BY 2.0

The glass spatula (or transparent plastic) can be used for measuring the efflorescences. Through spatula, pressure is made on the efflorescence, by which bleedings (erythema, which cannot be pushed away) can be distinguished from vascular dilations (which can be pushed away).

Incident light microscope (dermatoscope)


Image: “Dermatoscope (Heine, delta-10)” by Frank33. License: CC BY-SA 3.0

The dermatoscopy is a non-invasive procedure, which helps to assess the superficial skin layers by courtesy of a dermatoscope with a 10 – 100 times magnification. An important area where the dermatoscope is used is the classification of skin tumors (pigmented and non-pigmented).

Note: The ABCDE-rule for the evaluation of skin tumors: asymmetry, border (irregular), color, diameter (>5 mm) and evolution.

Image: “(a). Naked eye aspect: a 13mm black patch, with irregular borders; (b). Dermatoscopic aspect: a black rhomboidal structure, peripheric dots, irregular streaks and a central white-blue veil.” by Openi. License: CC BY 3.0


The medium frequency sonography (7.5 – 10 MHz) can present deep skin layers, veins, and lymphatic nodes. It is important e.g. for a basic diagnostic of malignant tumours: The primary tumor and regional lymphatic nodes are examined. The search for suspicious lymphatic nodes is conducted in the phase of planning and diagnostics as well as during follow-ups and therapy monitoring.

Sonography with a high frequency (20 – 50 MHz) is used for the examination of the epidermis, dermis and subcutis, e.g. for preoperative measuring of the thickness of a malignant melanoma.


The UVA-radiation (365 nm) of the wood-light can produce a colored fluorescence of hair and skin in case of specific skin alterations. A green fluorescence in case of microspore, red fluorescence in case of erythrism, white in case of onychomycosis and vitiligo is observed.

Histological procedure

In case of an unclarified diagnosis or to confirm a diagnosis a biopsy of the skin can be performed. In this procedure, parts of the skin changes are excised as a punching cylinder or a small spindle of the skin. After the fixation of the tissue sample, it can be histologically examined by microscope to detect and identify the skin disease.

Besides the evaluation of the epidermis, dermis and subcutis, it is possible to evaluate cancerous processes or autoimmunological illnesses by courtesy of immune histochemical procedures (antigen-antibodies-reaction) as well as immunofluorescence.

Review Questions

The answers are below the references.

1. The phenomenon of lichenification is defined in the field of dermatology as…

  1. …intraepidermal blistering.
  2. …loss of tissue in the area of multiple skin layers.
  3. …crack formed tears of brittle skin.
  4. …defect of substance, which goes up to the upper dermis.
  5. …thickening of the skin with coarsened lichenification.

2. An erosion of the skin…

  1. …heals without scars.
  2. …is a defect of substance, which goes up to the upper dermis.
  3. …never reaches the epidermis.
  4. …is defined as a cavity, filled with pus.
  5. …heals always with scarring.

3. A white dermographism is a diagnostic hint for…

  1. …lichen ruber.
  2. …psoriasis pustulosa.
  3. …atopic diathesis.
  4. …atrophy of the skin, because of the age.
  5. …tinea corporis.
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