Dermatology Memory - Answers

8/11/2019 Dermatology Memory - Answers

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Dermatology for the Primary CarePhysician

Sandy Baumberger, MD Assistant Professor

Dept. of Family

Medicine





Acanthosis Nigricans

Diffuse velvety thickening & hyperpigmentation ofthe skin. Most often the axilla, other body folds

May be associated with factors of heredity, obesity,endocrine disorders (metabolic syndrome), drugadministration (Nicotinic acid), and malignancy(adenocarcinoma, lymphoma)

May be caused by hypersecretion of pituitary peptide

or non-specific growth-promoting effect ofhyperinsulinemia

No specific treatment. May resolve with resolution ofcausative agent (drug) or weight loss





Allergic Contact Dermatitis

Acute, subacute, or chronic inflammation of theepidermis and dermis caused by external agents,

toxicity, or an allergic reaction characterized bypruritis or burning of the skin

Caused by a type IV hypersensitivity reaction causedby sensitized lymphocytes (T cells) after contact withan antigen. Tissue damage occurs from cytotoxicityby T cells and release of lymphokines

Treatment involves removing the offending agent,corticosteroid creams, and oral prednisone forreactions over large body surfaces





Atopic Dermatitis

Acute, subacute, usually chronic pruritic inflammation of theepidermis and dermis occurring in association of personal orfamily history of hay fever, asthma, rhinitis, or Atopic dermatitis

Type I (IgE mediated) hypersensitivity reaction occurring as aresult of the release of mast cells and basophils that have beensensitized by the interaction of the antigen with IgE.Colonization of Staph aureus of nares and/or involved skin isoften seen

Emotional stress worsens. Treatment with antihistamines to

decrease scratching and secondary infection. Topicalcorticosteroids are the mainstay of treatment. Occasionalsystemic steroids may be needed. Avoid superinfection withHSV and/or Staph aureus-treat if infection noted





Basal Cell Carcinoma

Most common type of skin cancer. Rarely metastasizes butmay invade deeply (especially in the “danger zones” near eyes,nasolabial folds, ear canal, and in posterior auricular sulcus.

Caused by sun exposure and or other radiation exposure Lesions appear as papule or nodule. May appear “pearly” with

a rolled edge. Fine telangiectasia may be seen. Variablecolors

Dermatopathology shows proliferating atypical basal cells(deep blue staining on H&E but with little anaplasia and

infrequent mitoses) Treatment involves excision with primary closure, skin flaps, or

grafts. Lesions in the danger zone should be removed viaMohs surgery. Radiation may be used in cases where severedisfigurement may occur with surgery





Candidiasis

Superficial mycotic infection occurring on moist cutaneous sitesand mucosal surfaces. Patients may have altered immunityfrom moisture at site of infection, diabetes, antibiotic therapy, oralteration in systemic immunity.

Microscopic sampling of skin or mucosal scraping shows C.albicans

Many sites potentially infected: mucosa, vulvovaginitis, diapercandidiasis, intertriginous, follicular, and chronic cutaneous

candidiasis Treatment involves topical or systemic treatment with antifungal

creams/tablets. Prevention includes procedures to avoidconstant skin contact with moisture





Erythema Multiforme

Reaction pattern of blood vessels in the dermis with secondaryepidermal changes with characteristic erythematous iris-shapedpapules and vesicobullous lesions. Typically involves withpalms, soles, and mucous membranes. May be pruritic orpainful

Dermatopathology shows inflammation characterized byperivascular mononuclear infiltrate, edema of upper dermis,and eosinophilic necrosis of keratinocytes if bulla formation

Treatment is symptomatic. If severely ill, doses of prednisone(50-80 mg/day). Control of Herpes Simplex outbreaks usingoral Acyclovir may prevent development of recurrent erythemamultiforme





Granuloma Annulare

Self-limited chronic inflammation of the dermis that

exhibits papules in an annular arrangement

Dermatopathology shows foci of chronic

inflammatory and histiocytic infiltrations in the

superficial and mid-dermis surrounded by a wall of

palisading histiocytes and multinuclear giant cells

Treatment with intralesional triamcinolone acetonide3.0 mg/ml or topical corticosteroids with occlusion

may be useful. May recur.





Herpes Simplex

Cutaneous infection caused by HSV 1 and 2 virus types. Type1 usually occurs above the waist/Type 2 below the waist.Lesions to mucous membranes are first umbilicated and thenevolve into punched-out lesions. Secondary infections withStaph aureus are common.

Wright’s stain of vesicular fluid shows multinucleated giantcells. Skin infection positive for HSV and may grow Staph.

Treatment with acyclovir 200 mg 5x daily for 5-10 days. Treat

staph infections with sensitive antibiotics. People with atopic dermatitis are at high risk, also people with

burns, and decreased immune states are at high risk.





Herpes Zoster

Acute localized infection caused by varicella-zoster virus (VZV)and is characterized by unilateral pain and vesicular or bullouseruption limited to a dermatome innervated by a corresponding

sensor ganglion. During the varicella virus, VZV travels to the sensory ganglion

and establishes latent infection. When humoral and cellularimmunity ebbs, viral replication occurs. The virus then travelsdown the sensory nerve causing pain first, then skin lesionsoccur.

Treatment with high dose Acyclovir (800 mg 5x daily for 10days) hastens healing of acute lesion. The risk of postherpeticneuralgia in patients over 60 years old is >50%. Disseminationmay occur, and motor paralysis may occur if the virus involvesthe cranial nerves.





Impetigo

An acute purulent infection which is at first vesicular and

later crusted-a very superficial infection of the epidermis

affecting mostly young children and young adults. Very contagious

Most often due to Staph aureus or group A B-hemolytic

streptococci

Treatment: wash crusts off - topical mupirocin 2%ointment. Systemic antibiotic therapy may be necessary

with sensitive antibiotics if extensive lesions are present.





Keratocanthoma

Self-healing, rapidly developing epithelial neoplasmthat mimics squamous cell carcinoma. May grow to

2.5 cm diameter in six weeks. HPV has been identified in some lesions. Other

etiologic factors include ultraviolet radiation andchemical carcinogens (industrial).

Spontaneous regression in 2-6 months, sometimes 1year. No specific treatment. May result indisfiguring scar. May need to biopsy-as lesion canmimic squamous cell carcinoma.





Systemic Lupus Erythematosus

Serious multisystem disease involves connective tissue andblood vessels. Clinical manifestations include fever, skinlesions, arthritis, renal, cardiac, and pulmonary disease.

Lesions may appear in “butterfly” pattern to face. Well-demarcated regions.

Dermatopathology shows atrophy of epidermis, dermalinflammatory infiltrate with lymphocytes, and fibrinoiddegeneration of the connective tissue and walls of the bloodvessels.

Treatment involves rest, avoidance of sun exposure.Prednisone is used for treatment of systemic symptoms.Chloroquine sulfate or other antimalarials are sometimes usefulin the treatment of skin lesions, but do not reduce the need forprednisone





Malignant Melanoma (nodular type)

One type of primary melanoma that arises quite rapidly (4 mosto 2 years) from normal skin or a melanotic nevus. 15-30% ofmelanoma in the US. Family history, light skin color, excessive

sun exposure, history of melanocytic nevus important. Appear on upper back in males, lower legs in females, and

other sites. Arises at the dermoepidermal junction and extendslaterally in the dermis. Eventually invades the dermis and thenmay continue to spread. Malignant melanoma is the type ofskin cancer most likely to metastasize.

Excisional or punch biopsy acceptable. Depth of lesion is moreimportant than diameter. Nodal biopsy only needed if >1.7 mmthickness or suspicion of node involvement. Skin grafts may beneeded for large areas





Molluscum contagiosom

Discrete, umbilicated, pearly-white papulescaused by a poxvirus and occur in both

children and adults that develop over 2-3months. Not symptomatic.

Dermatopathology reveals “molluscumbodies” (inclusion bodies)

Usually spontaneous remission. May usecurettage, liquid nitrogen, or lightelectrocautery





Onychomycosis

Dermatophyte infection of the nail plate. The termonychomycosis includes infections caused by both fungus andyeasts.

May occur due to reduction in blood flow with age or peripheralnerve injury. Mechanical pressure by footwear can also causeinjury and increase susceptibility of nail keratin todermatophytic infections.

Oral antifungals such as Terbinafine 250 mg 1x daily for 6-12

weeks or Sporanox 200mg 2x daily for 1 week and then 3weeks off, then retreat x1 week. Need to watch liver functions.





Pediculosis Captitis (Head Lice)

Infestation of the scalp by the head louse. It feedson the scalp and neck, and deposits eggs on the

hair. Minimal symptoms. Pediculus humanus capitis-transmitted via shared

caps, brushes, combs, head-to-head contact.

Treatment with Permethrin 1% cream. Apply toscalp after washing hair. Leave on scalp x 10minutes, rinse. Remove nits with fine tooth comb.Repeat after 7 days if living lice still present.Wash/dry-clean clothes/bedding as appropriate.





Pityriasis Rosea

Exanthematous, maculopapular, red, scalingeruption that occurs mainly on the trunk.

Causes pruritis for some-may be severe. “herald patch” precedes the exanthematous

phase. The exanthem develops over aperiod of 1-2 weeks. Thought to be caused

by an unknown infectious agent.

Regression is usually spontaneous. May useUVB treatments, antihistamines for pruritis.





Psoriasis

Psoriasis affects 1.5-2% of the population of western countries.Hereditary skin disorder causing chronic scaling papules andplaques in a characteristic distribution. Pruritis is common.

Papules and plaques with silvery-white scale. Pustules may bepresent.

Alteration in the cell kinetics of keratinocytes. The cell cycleshortens from 311 to 36 hours. 35,000 epidermal cells areproduced per day. In HLA-B28 variant-may be associated witharthritis. Nails may be affected.

Discourage scratching as this accelerates the proliferativeprocess. Treat with topical agents. Use the lowest potencyformulation for the shortest length of time. Phototherapy andsystemic corticosteroids may be needed for widespreadlesions.





Scabies

Skin infestation by a mite. Usually spread by skin-to-skin contact and causes intractable pruritis with

frequent secondary bacterial infection.Misdiagnosed scabies is what the term “seven yearitch” is based on.

Sarcoptes scabiei is the causative mite.

Treatment with Permethrin 5% cream applied toentire body and then rinsed after 8-12 hours. Euraxmay be used in pregnancy. Treat entire family, andwash all clothes and linens.





Squamous Cell Carcinoma

Malignant tumor of epithelial keratinocytes. Arises as a resultof exogenous carcinogens (sunlight exposure, exposure toionizing radiation, & other causes). Persons who work outdoors

and have fair skin at higher risk.

Dermatopathology shoes proliferating anaplastic cells thatextend in broad masses into the dermis and SQ tissue.

Treatment involves wide excision. SCC has an overallremission rate after therapy of 90%. Lesions from ionizing

radiation or in an old burn scar are more likely to metastasize.Low rate of metastasis overall. Patients outdoors often need touse sunscreen with high SPF and protective clothing. Avoidtanning beds.





Tinea Capitis

Dermatophytic infection of the scalp. Acute infectioncharacterized by follicular inflammation with painful, boggynodules which drain pus and result in scarring alopecia.

Scaling alopecia is seen in chronic infection.Lymphadenopathy may be seen.

Microsporum audouini, M. canis, Trichophyton tonsurans arecausative agents. May be transmitted person-to-person, or pet-to-person, or via hats, barber utensils.

Treatment with Griseofulvin orally for 1-2 months usuallyneeded. Watch liver functions if on drug for several months.Infection may recur.









Varicella

Highly contagious primary infection characterized bysuccessive crops of pruritic vesicles which evolve topustules, crusts, and at times scars. Mildconstitutional symptoms. Known as “Chickenpox”.

Caused by Varicella Zoster virus

Varicella vaccine given routinely now-required forschool admission. Treatment is usuallysymptomatic. Adults may require treatment with

Acyclovir 800 mg 4x daily for 5 days within 24 hoursof illness. May give VZIG to immunocompromisedpatients if exposed to VZV.





Verruca Vulgaris (Common Wart)

A discrete benign epithelial hyperplasia

manifested by papules and plaques caused

by viral infection.

Caused by human wart viruses of the papova

group, HPV.

Treatment using salicylic acid, liquidnitrogen, curettage with local anesthesia, or

laser surgery



Cellulitis

Cellulitis is a spreading infection of the skinextending to involve the subcutaneous tissues.

The most common causes are group A ß -haemolytic streptococci (GABHS) andStaphylococcus aureus.

Predisposing factors include skin abrasions,lacerations, burns, eczematous skin, etc,

although the portal of entry of organisms is oftennot seen.

Treat with flucolaxacillin

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Dermatology Memory - Answers

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