Dermatologic Disorders
Dermatologic conditions are usually described by the types of lesions that appear on the skin,
their shape, and configuration.
Types of skin lesions
Primary Lesions
Macula: flat, circumscribed discoloration of skin; may have any size or shape.
Papule: solid, elevated lesion less than 1 cm wide.
Nodule raised, solid lesion larger than 1 cm wide.
Vesicle: round elevated lesion less than 1 cm, containing fluid.
Bulla: a vesicle or blister larger than 1 cm wide.
Pustule: round raised lesion that contains pus; may form as a result of purulent
changes in a vesicle.
Wheal: elevation of the skin that lasts less than 24 hours, caused by edema of the
dermis.
Plaque: solid, elevated lesion on the skin or mucous membrane, larger than 1 cm in
diameter; psoriasis is commonly manifested as plaques on the skin; leukoplakia is an
example of plaques on mucous membranes.
Cyst soft or firm mass in the skin, filled with semisolid or with liquid material
contained in a sac.
Secondary Lesions
Secondary lesions involve changes that take place in primary lesions that modify them.
Scale heaped-up, horny layer of dead epidermis; may develop as a result of
inflammatory changes.
Crust covering formed by the drying of serum, blood, or pus on the skin.
Excoriation: linear scratch marks or traumatized areas of skin.
Fissure: cracks in the skin, usually from marked drying and long-standing
inflammation.
Ulcer: lesion formed by local destruction of the epidermis and by part or all of the
underlying dermis.
Scar: new formation of connective tissue that replaces the loss of the dermis as a
result of injury or disease.
, Atrophy diminution in size of skin cells that causes thinning of the skin.
DIAGNOSTIC TESTS
LABORATORY TESTS
Some dermatologic conditions can be evaluated by laboratory tests of microscopy and
culture.
1. Microscopy
Sample taken by scraping, swabbing, or aspirating a lesion is transferred to a glass
slide for observation or staining.
o Direct visualization of scrapings mixed with mineral oil to detect scabies, mites, or
lice nits that cling to hair.
o A Tzanck smear is obtained from vesicular fluid or a moist ulcer and stained to
detect characteristics of herpes simplex virus, herpes zoster, and varicella.
o Potassium hydroxide may be added to skin scrapings on a glass slide and heated to
dissolve skin cells to detect hyphae and spores in fungal infections.
o Gram stain may be performed to tentatively identify bacteria in certain skin
infections.
Nursing and Patient Care Considerations
Use the side of a glass slide or a scalpel held at a 45-degree angle to gently scrape the
skin of a dry lesion or of an inflamed area; only mild discomfort and pinpoint
bleeding should occur.
For moist or semimoist ulcerations or crusted lesions, roll a saline-soaked cotton or
Dacron-tipped swab over the lesion; for weeping lesions, use a dry swab.
For intact vesicles, aspirate fluid from the edge with a 25-gauge sterile needle; if
vesicle is partially broken, gently unroof with forceps and obtain fluid on a swab.
Culture
Drainage from lesions may be cultured on specific media to detect causative organism
and sensitivity to antimicrobial therapy; also, portions of skin, hair, and nails may be
submitted for fungal culture.
Usually takes 24 to 48 hours for results; fungal cultures may take 4 to 5 weeks.
2. Patch Testing
Patch testing is dermatology to determine if patients are allergic to contact materials.
Materials are applied on skin patches and checked for reaction 48 hours after application.
,Erythema, swelling, papules, and vesicles indicate an allergic contact dermatitis.
A final reading will be done on your next visit, which will take place 96 hours after
the disks have been removed.
SKIN BIOPSY…….
It is the removal of a piece of skin excision technique to detect malignancy or other
characteristics of skin disorders.
Types of biopsy
- Shave biopsy scalpel used to remove raised lesions, leaving lower layers of dermis intact.
- Punch biopsy special instrument used to remove round core of lesion, containing all
layers of skin. Core is usually closed with sutures.
- Excisional biopsy scalpel and scissors used to remove entire lesion; suturing required.
Nursing Considerations
Position the patient comfortably with the site exposed
Explain the procedure.
Obtain written consent.
After the biopsy, apply pressure to the site to stop bleeding if required and apply an
appropriate dressing.
Place the biopsy specimen in a clearly labeled container with 10% formaldehyde and
transport it to the lab.
WOUND COVERAGE: GRAFTS AND FLAPS
Wound coverage, using grafts and flaps, is a type of reconstructive (plastic) surgery
performed to improve the skin's appearance and function.
Skin graft
A section of skin tissue is separated from its blood supply and transferred as free
tissue to a recipient site;
The graft obtains nourishment from capillaries at the recipient site.
In dermatology, skin grafting is used to repair defects that result from excision of skin
tumors or severe burn.
Definitions
- Autografts grafts done with tissue transplanted from the patient's own skin.
- Allografts involve the transplant of tissue from one individual of the same species; these
grafts are also called allogenic or homografts.
, - Xenograft or heterograft involves the transfer of tissue from another species.
Classification of grafts by thickness
- Split thickness (thin, intermediate, or thick) graft that is cut at varying thicknesses and is
used to cover large wounds because its total potential donor area is virtually unlimited.
- Full thickness graft consists of epidermis and all of the dermis. It is used to cover
wounds that are too large to close primarily.
They are used frequently to cover facial defects because they provide a better contour match
and less postoperative contracture.
Skin Flaps
- A flap is a segment of tissue that has been left attached at one end (called a base or
pedicle); the other end is moved to a recipient area.
- It is dependent for its survival on functioning arterial and venous blood supplies and on
lymphatic drainage in its pedicle or base.
- Flaps may consist of skin, mucosa, muscle, adipose tissue, and omentum.
- Used for wound coverage and to provide bulk, especially when bone, tendon, blood
vessels, or nerve tissue are exposed.
Flaps offer the best aesthetic solution because a flap retains the color, texture, and
thickness match of the donor area.
Procedure for Skin Grafts
Split-thickness skin graft is obtained by razor blade, skin-grafting knife, electric, or
air-powered dermatome/drum dermatome. Most commonly obtained from the inner
aspect of the upper arm or outer thigh.
A full-thickness skin graft is primarily excised, defatted, and tailored to fit accurately
over the defect area.
Skin is taken from the donor or host site and applied to the recipient site or graft bed.
The donor site is maintained clean and dry.
Preoperative Management and Nursing Care
Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) and vitamin E are
discontinued 14 days before the procedure.
Prothrombin time should be measured before the procedure as ordered.
Efforts should be made to enhance wound healing several months to several weeks
before the procedure, such as smoking cessation, alcohol avoidance, and proper
nutrition.