Dermatology Flashcards
1–2 mm papules and pustules are distributed on the face and scalp.
Lesions are present at birth or within the first 2–4 weeks of life.
Comedones are absent.
What disorder has these findings?
Neonatal acne
Explanation
Neonatal acne typically resolves spontaneously within the first 2–3 months of life. The etiology is controversial. Some consider it to be a hypersensitivity reaction to Malassezia furfur. Neonatal acne is sometimes confused with miliaria rubra or cutaneous candidiasis. Treatment consists only of daily cleansing with soap and water. The condition does not scar and usually resolves spontaneously within 3 months. Note that there is a difference between neonatal and infantile acne
A child presents with the following:
Dandy-Walker syndrome
Hemangioma that is large, involving the cervicofacial area, including CN 5 (1)
Intracerebral arterial anomalies
Coarctation of the aorta
Microphthalmia
What is the syndrome presented here?
Answer
PHACE(S) syndrome
Explanation
PHACE(S) syndrome occurs with large, segmental facial hemangiomas.
P—posterior fossa abnormalities (Dandy-Walker)
H—hemangioma (generally large, cervicofacial lesions involving cranial nerve 3 distribution)
A—arterial anomalies (typically intracerebral arterial anomalies)
C—cardiac defects, especially coarctation of the aorta
E—eye abnormalities (microphthalmia)
S—sternal defects/supraumbilical raphe
Infants with port-wine stains of the lower extremities are at risk for what syndrome?
Klippel-Trenaunay syndrome (KTS)
Explanation
KTS presents with a vascular malformation (often mixed capillary-venous-lymphatic) of an extremity, with soft tissue and/or limb overgrowth and varicose veins. Limb overgrowth is generally progressive in nature.
A 9-year-old girl with a history of atopic dermatitis now presents with areas of hypopigmentation with a fine scale, mostly affecting the cheeks and extensor extremities.
What is the most likely diagnosis?
Pityriasis alba
Explanation
Pityriasis alba is common in school-age children with atopic dermatitis and presents as described. It is more apparent on children with darker skin and during summer because the affected skin does not tan normally. It usually affects the cheeks and extensor extremities. The face is the only area affected in up to 50% of cases. Patches vary from 1 cm to 4 cm in size and usually range between 5 and 20 in number. Treatment of pityriasis alba is primarily symptomatic and consists of appropriate general skin care, education about the benign nature of the disorder, and low-potency topical corticosteroid creams and emollients. Sun protection can help prevent tanning of the surrounding skin, which makes the condition more apparent
Is poison ivy spread by fluid contained in the vesicular or bullous lesions?
No
Explanation
Poison ivy can only be spread by contact with the plant resin. If the patient or their clothes have not been washed and still contain the poison ivy resin, then it can spread that way!
Treatment of allergic contact dermatitis, such as poison ivy, consists of removal of the antigen, cool compresses (Burow compress [aluminum acetate] is helpful for weepy lesions), topical glucocorticoids, and emollients. If severe, such as extensive poison ivy dermatitis on the face, give systemic glucocorticoids for 14 days. Shorter courses can lead to rebound flaring
A newborn presents with 1–2 mm firm, white papules that appear on the surface of pilosebaceous units on the face.
What is the most likely diagnosis?
Milia
Explanation
Milia are 1–2 mm firm, white papules, most commonly on the face. These tiny epidermal inclusion cysts generally resolve spontaneously over several months and require no treatment
What causes Stevens-Johnson syndrome (SJS)?
Severe drug reactions
Explanation
SJS presents with skin sloughing and mucous membrane involvement. The most common culprits are sulfa antibiotics and the aromatic antiseizure medications (phenytoin, phenobarbital, or carbamazepine). Treatment consists of discontinuing the offending drug, monitoring for internal organ involvement, and supportive care in a hospital setting with skilled nursing, often in burn units.
A child has a herpes simplex skin infection and develops target-like lesions on the palms and soles. He now has mild mucous membrane involvement as well.
What is the most likely diagnosis?
Erythema multiforme (EM)
Explanation
EM consists of well-defined lesions that evolve into target shapes. Palms and soles are frequently involved and mucous membranes may be affected. The target-shaped lesions are pathognomonic for EM and are characterized by a central blister or zone of necrosis/crusting. EM is further subdivided into EM minor and EM major. Both forms have the target lesions; however, in contrast to EM minor, EM major has mucosal involvement and patients can be systemically ill. The fixed target lesions last for several days (a minimum of 7 days) before resolving spontaneously
Fine, white scales without redness on the extensor surfaces of the extremities
Improvement to rash in hot, humid climates and during the summer
Hyperlinear palms and soles
Caused by loss-of-function mutations in the gene encoding filaggrin
Autosomal dominant
What disease has these characteristics?
Answer
Ichthyosis vulgaris
Explanation
Ichthyosis vulgaris is the most common ichthyosis, occurring in 1/250 people. It is transmitted in an autosomal dominant fashion. Most commonly, the condition first manifests after 3 months of age. Treatment is irritant avoidance and use of emollients and keratolytic products.
What virus is the most common cause of erythema multiforme (EM)?
Herpes simplex virus (HSV)
Explanation
EM is typically a reactive process to a viral illness, classically HSV Type 1. HSV Type 1 ( herpes labialis) is the most common culprit. EM is subdivided into EM minor and EM major, the difference being that EM major has mucosal involvement and patients can be systemically ill. Mycoplasma pneumoniae, other viruses (e.g., Epstein-Barr virus, adenovirus, HIV, CMV), medications, and autoimmune diseases have also been linked to EM.
You diagnose a boy in the 1st few weeks of life with X-linked recessive ichthyosis.
What is associated with this disorder, and what should you check for in this boy?
Answer
Undescended testes with underdeveloped penis and scrotum
Explanation
X-linked recessive ichthyosis occurs in 1/2,000–6,000 boys and generally is apparent at birth or during the 1st few months of life. The scales are more pronounced compared to the autosomal dominant form. The trunk is involved, but not the palms and soles. It is caused by the absence of the microsomal enzyme steroid sulfatase. These genitourinary (GU) abnormalities are common in this disorder, with an associated increased risk of testicular cancer. Perinatally, this disorder can cause prolonged labor. Affected boys can have cryptorchidism, with an associated increased risk of testicular cancer. If this diagnosis is suspected, patients need a thorough GU exam. Treatment of the ichthyosis consists of regular bathing and using emollients and keratolytics.
In a patient with extremely severe seborrhea, what diagnosis should you consider?
Answer
Langerhans cell histiocytosis
Explanation
Consider this particularly if atrophy, ulceration, or petechiae are present. Send for skin biopsy to diagnose.
What skin condition consists of red, tender, warm nodules that appear on the shins and is associated with infection (e.g., TB, β-hemolytic streptococcal, deep fungal), drugs (e.g., oral contraceptives, sulfas, penicillins), Behçet disease, sarcoidosis, and inflammatory bowel disease in children?
Answer
Erythema nodosum (EN)
Explanation
EN is associated with sarcoidosis, but in children, it is more commonly due to infection, drugs, or inflammatory bowel disease. It is often idiopathic, but the most common identifiable cause is streptococcal pharyngitis. EN is a reactive process—removal or treatment of the inciting trigger often results in resolution of the EN. Other treatments include rest, elevation, and NSAIDs
According to the American Academy of Pediatrics 2021 Red Book, should children be excluded from school or sent home early from school because of head lice?
No
Explanation
The child does not need to be sent home early. They can stay at school till the end of the day and can return once treatment has begun. “No-nit” policies requiring children to be free of nits before returning to school are not effective in preventing the spread of head lice. They are explicitly discouraged by the 2021 Red Book.
Papules and pustules with open and closed comedones distributed over the face:
Absent at birth
Appear at 2–4 months of age
More common in boys
Identify the disorder that includes these characteristics.
Answer
Infantile acne
Explanation
Infantile acne can be contrasted with neonatal acne based on the timing (infantile acne has a later onset) and the lesions (comedones are present in infantile acne). Infantile acne, unlike other lesions, generally requires therapy with topical benzoyl peroxide or antibiotics. It is caused by androgenic stimulation of the sebaceous glands. Infantile acne is potentially persistent and severe cases cause scarring. The condition usually resolves over 6–12 months. Rarely, infantile acne is due to pathologic states of androgen excess, such as congenital adrenal hyperplasia, adrenal tumors, or precocious puberty. If these conditions are suspected, appropriate blood work must be done to further evaluate the cause of infantile acne (e.g., measure 17-hydroxyprogesterone levels
