Contact Dermatitis

A 27-year-old woman developed the pictured lesion 2 days after wearing a new pair of earrings. What is the most likely diagnosis?

A   Atopic dermatitis

B   Irritant dermatitis

C.  Nummular dermatitis

D   Seborrheic dermatitis

E    Allergic dermatitis

Option A (Atopic dermatitis) is incorrect. Atopic dermatitis is a subacute and chronic

dermatitis that is often called an itch that rashes. It has dry, scaly, pruritic patches and

plaques with excoriations located in the flexural regions.

Option B (Irritant contact dermatitis) is incorrect. Irritant contact dermatitis is the result of direct toxic injury to the skin and will occur in any individual given sufficient exposure. This is in contrast to allergic contact dermatitis, where individuals with atopy are more likely to develop it. Irritant contact dermatitis is differentiated from allergic contact dermatitis by the acute speed of the reaction (less than 12 hours usually), a very sharp border without spread and an absence of papules in the acute phase.

Option C (Nummular dermatitis) is incorrect. Nummular dermatitis presents as pruritic, coin-shaped erythematous plaques that are dry and scaly.

Option D (Seborrheic dermatitis) is incorrect. Seborrheic dermatitis presents with a

greasy, yellow, erythematous, scaly plaque primarily in the perioral area or other areas rich in sebaceous glands, such as the scalp margin and sternum.

Option E (Allergic contact dermatitis) is correct. This patient has allergic contact dermatitis, most likely the result of nickel in her new earrings. Allergic contact dermatitis should be suspected when there is exposure to an allergen and a reaction develops at least 48 hours later. As pictured,  there in an erhythematous base and a slightly white scale with a defined border.

CONTACT DERMATITIS

BASIC INFORMATION

Contact dermatitis is an acute or chronic skin inflammation, usually eczematous dermatitis resulting from exposure to substances in the environment. It can be subdivided into "irritant" contact dermatitis (nonimmunologic physical and chemical alteration of the epidermis) and "allergic" contact dermatitis (delayed hypersensitivity reaction).

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IRRITANT CONTACT DERMATITIS:

Primary irritant dermatitis (80%) is due to direct injury of the skin. It affects individuals exposed to specific irritants and generally produces discomfort immediately after exposure.

· Mild exposure may result in dryness, erythema, and fissuring of the affected area

(e.g., hand involvement in irritant dermatitis caused by exposure to soap, genital area

involvement in irritant dermatitis caused by prolonged exposure to wet diapers).

· Eczematous inflammation may result from chronic exposure.

ALLERGIC CONTACT DERMATITIS:

Allergic contact dermatitis (ACD) (20%) affects only individuals previously sensitized to the contactant. It represents a delayed hypersensitivity reaction, requiring several hours for the cascade of cellular immunity to be completed to manifest itself.

· Poison ivy dermatitis can present with vesicles and blisters; linear lesions (as a result

of dragging of the resins over the surface of the skin by scratching) are a classic

presentation.

· The pattern of lesions is asymmetric; itching, burning, and stinging may be present.

· The involved areas are erythematous, warm to touch, swollen, and may be confused

with cellulitis.

System(s) affected: Skin/Exocrine

Genetics: Increased frequency of ACD in families with allergies.

Incidence/Prevalence in USA: Contact dermatitis represents >90% of all occupational skin disorders.

Predominant age: All ages

Predominant sex: Male = Female. Variation due to differences in exposure to offending agents as well as normal cutaneous variation between male and female (eccrine and sebaceous gland function and hair distribution).

SIGNS & SYMPTOMS:

Acute

Papules, vesicles, bullae with surrounding erythema

Crusting and oozing may be present

Pruritus

Chronic

Erythematous base

Thickening with lichenification

Scaling

Fissuring

Distribution

Where epidermis is thinner (eyelids, genitalia)

Areas of contact with offending agent (nail polish)

Palms and soles more resistant

Deeper skin-folds spared

Linear arrays of lesions

Lesions with sharp borders and sharp angles -- pathognomonic

CAUSE

Plants

Rhus-urushiol (poison ivy, oak, sumac)

Primary contact – plant (roots/stems/ leaves)

Secondary contact – clothes/fingernails (not blister fluid)

Chemicals

Nickel – jewellery, zippers, hooks, watches

Potassium dichromate – tanning agent in leather

Paraphenulenediamine – hair dyes, fur dyes, industrial chemicals

Turpentine – cleaning agents, polishes, waxes

Soaps, detergents

×            

×            

Topical medicines

Neomycin – topical antibiotics

Thimerosal (Menthiolate) – preservative in topical medications

Anesthetics – benzocaine

Parabens – preservative in topical medications

Formalin – cosmetics, shampoo, nail enamel

SIMPLIFIED ETHIOLOGY

· Irritant contact dermatitis: cement (construction workers), rubber, ragweed, malathion

(farmers), orange and lemon peels (chefs, bartenders), hair tints, shampoos

(beauticians), rubber gloves (medical, surgical personnel)

· Allergic contact dermatitis: poison ivy, poison oak, poison sumac, rubber (shoe

dermatitis), nickel (jewellery), balsam of Peru (hand and face dermatitis), neomycin,

formaldehyde (cosmetics)

RISK FACTORS

×           Occupation

×           Hobbies

×           Travel

×           Cosmetics

×           Jewellery

DIAGNOSIS

LABORATORY TESTS

· Patch testing is useful to confirm the diagnosis of contact dermatitis; it is indicated

particularly when inflammation persists despite appropriate topical therapy and

avoidance of suspected causative agent; patch testing should not be used for irritant

contact dermatitis because this is a nonimmunologic-mediated inflammatory reaction.

· Gram stain and cultures are indicated only in cases of suspected secondary infection

or impetigo.

 Patch tests for allergic contact dermatitis (systemic corticosteroid or recent, aggressive use of topical steroids may alter results)

TREATMENT

WORKUP

×           Medical history: gradual onset vs. rapid onset, number of exposures, clinical

×           presentation, occupational history

×           Physical examination: contact dermatitis in the neck may be caused by necklaces,

×           perfumes, after-shave lotion; involvement of the axillae is often secondary to

×           deodorants, clothing; face involvement can occur with cosmetics, airborne allergens,

×           aftershave lotion

General Measure

×           Removal of offending agent

×           Topical soaks with cool tap water, Burrow’s solution (1:40 dilution), or saline ( 1 tsp/pint water), or silver nitrate solution

×           Lukewarm water baths – antipruritic

×           Aveeno (oatmeal) baths

×           Chronic – emollients (white petrolatum, Eucerin)

×           Surgical Measures: N/A

×           Activity: Stay active, but avoid overheating

×           Diet: No special diet

×           Patient Education:

×           Avoidance of irritating substance

×           Cleaning of secondary sources (nails, clothes)

×           Fallacy of blister spreading disease

MEDICATION:

×           DRUG(S) OF CHOICE

v  Topical

×           Shake lotion of zinc oxide, talc, menthol 0.25%, phenol 0.5%

×           Corticosteroids: high potency steroids, fl uocinonide (Lidex) 0.05% ointment 3-4 times daily. Caution regarding face/skinfolds - use lower potency steroids and avoid prolonged usage. Switch to lower potency topical steroid once acute phase resolved. Avoid prolonged use.

×           Calamine lotion

×           Topical antibiotics for secondary infection (bacitracin, gentamicin, erythromycin)

v  Systemic

 Antihistamine: hydroxyzine 25-50 mg qid, diphenhydramine 25-50 mg qid

×           Corticosteroids: prednisone. Taper starting at 60-80 mg/d, tapered over 10-14 days.

×           Antibiotics: erythromycin 250 mg qid if secondarily infected

×           Dicloxacillin 250 mg po qid for 7-10 days or amoxicillin- clavulanate (Augmentin) 500 mg po bid for 7-10 days for secondary bacterial infection

×           Contraindications: N/A

×           Precautions:

•      Drowsiness from antihistamines

•      Local skin effects: atrophy, stria, telangiectasia from prolonged use of potent topical steroids

×           Significant possible interactions: N/A

×           ALTERNATIVE DRUGS Other topical antibiotics depending on organisms and sensitivity

FOLLOWUP

PATIENT MONITORING

×           As necessary for recurrence

×           Patch testing for etiology after resolved

PREVENTION/AVOIDANCE

×           Avoid causative agents. Use of protective gloves (with cotton lining) may be helpful.

POSSIBLE COMPLICATIONS

×           Generalized eruption secondary to autosensitization

×           Secondary bacterial infection

EXPECTED COURSE/PROGNOSIS

×           Self-limited, benign

AGE-RELATED FACTORS

×           Pediatric: Younger individuals - increased incidence of positive patch testing due to better delayed hypersensitivity reactions

×           Geriatric: Increased incidence of irritant dermatitis secondary to skin dryness

×           Others: N/A

×           PREGNANCY Usual cautions with medications