Pediatric Dermatology

Pediatric Dermatology: Acne and Related Disorders

Acne Vulgaris

disorder of pilosebaceous apparatus (hair follicle and sebaceous gland) involving an overactive pilosebaceous unit to androgenic stimulation (e.g. testosterone, androsterone)

Pathogenesis: multifactorial disease that requires: (1) androgens, (2) sebaceous glands, (3) abnormal keratinization, and (4) bacteria

Process – Androgenic stimulant (external agent, follicular irritant, emotional stress) Þ increased sebaceous gland activity and altered microbial flora Þ abnormal keratinization traps debris, sebum, and bacteria forming a lesion (comedone) – a dilated hair follicle filled with sebum, keratin, and squamae (an epidermic scale) Þ Comedonal rupture produces a reactionary inflammation leading to an inflamed papule or pustule

Microbiology: Propionibacterium acnes, also Staphylococcus epidermidis

P. acnes increases at puberty and is part of the normal skin flora. Thus, Acne is not an infectious disease

Bacteria: hydrolyze triglycerides to FFAs; possess lipases, proteinases, hydrolases which cause release of inflammatic and chemotactic factors that attract neutrophils which damage the follicular wall leading to rupture

Clinical Presentation:

Onset can be early – before puberty. Can present on face, back, chest, shoulders, sometimes the buttocks
Lesion types: open and closed comedones, papules and pustules, nodules and scars
Primary lesion is a microcomedone – a hyperkeratotic follicle filled with debris. Becomes:

Open Comedone – "blackhead"; large pore with brown or black core of keratin or sebum (NOT dirt)

Closed Comedone –"whitehead"; difficult to see—inconspicuous opening
either comedone can develop into an inflammatory papule or pustule, or a nodule

Treatment: Diet: plays no role; topical agents (salicylic acid, benzoyl peroxide, tretinoin, topical antibiotics, glycolic acids);

systemic agents (antibiotics, retinoids, birth control pills); intralesional corticosteroids, comedone extraction.

Folliculitis

caused by Staph aureus (most common), Pityrosporum yeast, P. aeruginosa ("hot tub folliculitis")

Any hair bearing portion of the body may be involved.

Superficial folliculitis – infection of upper portion of pilosebaceous unit

Furuncles and carbuncles – infection of deeper portion of pilosebaceous unit

Treatment: topical or oral antibiotics, antimicrobial soaps

Vascular Malformations

Capillary hemangiomas – present at/near birth. Rapid growth first 6-12 mths into a bright purple/red, lobulated, well demarcated mass followed by partial or complete involution; solitary or multiple any area of the body

Cavernous hemangiomas – similar to capillary hemangioma except its a deeper lesion and mostly on head/neck

Salmon Patches – neck ("Stork bite"), glabella (angel’s kiss; between eyebrows; fades with time); variant of nevus flammeus

Nevus flammeus – "Port wine stain" - lesion common on face, will NOT fade but thickens with time. Treatment – Laser therapy

Neonatal Herpes Simplex Infection

any HSV during first month of life is considered neonatal HSV

Clinical presentation: 10% - cutaneous lesions; 30% - disseminated disease; 60% - cutaneous and disseminated disease; 50% of infected infants are born to mothers without history or signs of infection!

Dissemination includes: liver, spleen, pneumonities, coagulapathy, meningoencephalitis

Cutaneous lesions: vesicles on an erythematous base. Sometimes erythematous macule or ruptured vesicle
Non-neonatal HSV presents as classic vesicle on erythematous base.

Epidemiology: 1/3000 births. Risk of infection is 50% in mothers with primary genital infection

Treatment: systemic antivirals (Acyclovir). With ocular involvement use 3% vidarabine as well

Herpetic Gingivostomatitis

most common form of primary HSV infection. Nearly all cases are HSV-1

Clinical presentation: common from 6mths - 5yrs. Small vesicles (usually ruptured) on an erythematous base anywhere in the oral cavity. May have prodrome of irritability, fever, headache, nausea, and vomiting. Self limiting (3-4days)

Hand, Foot, and Mouth Disease

Coxsackie virus A16 (also A5, 7, 9, and 10)

Clinical presentation: mild prodrome of low fever, malaise, sore mouth, anorexia; 1 to 2 days after oral lesions develop, vesiculopustules with erythematous rims may develop on acral limbs; lips and gingiva spared (unlike herpes); cutaneous lesions more common in kids; self limiting, no treatment necessary

Impetigo

contagious superficial infection of the skin caused by Staph aureus, Group A Strep or both

small red macules develop into vesicles which rupture and release cloudy fluid which becomes crusted

Easily spread by autoinnoculation

Treatment: oral antibiotics with staph and strep coverage (semi-synthetic penicillins, cephalosporins)

Warts – Papovavirus (over 70 serotypes identified)

Clinical Manifestations:

Verruca vulgaris: Usually on hands. HPV Types 1,2, and 4.

Verruca plana: Flat warts on face, neck, and arms. HPV Types 2,3, and 10.

Plantar warts: Bottom of feet. Deep and painful. HPV 1

Condyloma accuminata: Genital warts. Fleshy growths in and around genitals. Can be carcinogenic. HPV 6,11,16,18,30,31

Epidemiology: Incubation is uncertain. Susceptibility varies. Can spread via skin contact.

Treatment: All treatment modalities have 50% recurrence rate. Blistering agents, laser, liquid nitrogen, debridement.

Exanthems – a skin eruption due to a viral or coccal disease

(1) Measles: paramyxovirus

Enanthem (mucous membrane eruption): Koplick’s spots (white papules on mouth). 2 days before the exanthem

Exanthem: erythematous macules and papules that start on the face and descend

Prodrome of fever, chills, malaise, headache, conjunctivitis, dry cough, nasal discharge

(2) Scarlet Fever: Group A b hemolytic streptococci, usually pharyngeal infection

Enanthem: white or red strawberry tongue, tonsillar exudate, palatal petechiae, red pharynx

Exanthem: erythematous punctate rash on upper trunk. Pastia’s lines – petechiae in skin folds

Prodrome of fever, headache, vomiting, malaise, and sore throat
Resolution after 4-5 days

(3) Rubella (German measles): Togavirus

Exanthem small rose-pink macules and papules on face that spread to trunk and extremities
typical lymph node enlargement; Infection during pregnancy can cause multiple birth defects

(4) Erythema Infectiosum: Parvovirus B19

Exanthem: begins as malar blush -"slapped cheeks"; Develops erythematous macules and papules on extermities

(5) Duke’s Disease: never really existed

(6) Roseola Infantum (exanthem subitum): Human herpes virus type 6

Exanthem: Discrete rose-pink macules on trunk that spreads to extremities and fades in 2-3 days

Prodrome: High fever for 3-5 days in children under 3 prior to the rash

Child Abuse – physical abuse, sexual abuse, and neglect

Clinical Manifestations: eccyhmoses on the hand and face, bites, burns

Epidemiology: 2 million children each year are abused with 2,000- 5,000 deaths. Accounts for 10% of ER visits by young children. Up to 95% of abused children have skin manifestations.