7 - ERYTHEMA AND URTICARIA

Question 1

Erythema multiforme minor is usually caused by

Answer 1

HSV infection

Question 2

Erythema multiforme major is most often caused by

Answer 2

Mycoplasma infection

Question 3

Recurrent self limited disease Sharply marginated, erythematous macules then evolve to papules Target lesions observed in palms and soles Koebner phenomenon

Answer 3

EM minor

Question 4

Type of EM: Frequently accompanied by a febrile prodrome Lesions on extremities and face, may include trunk Mucous membrane disease prominent

Answer 4

EM major

Question 5

Sharply marginated rapidly extending, tender, erythematous or violaceous, painful, elevated plaque, 2-10cm diameter Face, neck, upper trunk and extremities May burn but do not itch Fever

Answer 5

Sweet syndrome Acute febrile neutrophilic dermatosis

Question 6

Majority of cases of Sweet syndrome follow this infection

Answer 6

URTI

Question 7

Pregnancy associated Sweet syndrome usually presents in what trimester

Answer 7

1st or 2nd

Question 8

Treatment for Sweet syndrome

Answer 8

Self limited Oral prednisone 1mg/kg/day

Question 9

Begins as an inflammatory pustule with a surrounding halo that enlarges and begins to ulcerate Lower extremities and trunk

Answer 9

Pyoderma gangrenosum

Question 10

Least aggressive form of pyoderma gangrenosum

Answer 10

Vegetative

Question 11

Disease most often associated with pyoderma gangrenosum

Answer 11

IBD

Question 12

Most common inherited auto inflammatory syndrome

Answer 12

Familial Mediterranean fever

Question 13

Autosomal recessive Recurrent 12-72h of fever and monoarthritis and erysipela like erythema

Answer 13

Familial Mediterranean fever

Question 14

Treatment for familial Mediterranean fever

Answer 14

Colchicine

Question 15

Vascular reaction of the skin characterized by appearance of wheals surrounded by red halo or flare with severe itching Caused by localized edema

Answer 15

Urticaria

Question 16

Acute and chronic urticaria timeline

Answer 16

Acute <6 weeks Chronic >6 weeks

Question 17

Sharply localized edema or wheal with a surrounding erythematous flare after the skin has been stroked 2-5% of population

Answer 17

Dermatographism

Question 18

Cholinergic urticaria is produced by the action of acetylcholine on what cell

Answer 18

Mast cell

Question 19

Adrenergic urticaria is mediated by this hormone

Answer 19

Norepinephrine

Question 20

Management of cholinergic and adrenergic urticaria

Answer 20

Adrenergic- propranolol Cholinergic- antihistamines

Question 21

Angioedema in the absence of urticaria can be due to

Answer 21

Hereditary angioedema ACE inhibitor

Question 22

intense flushing may be associated with

Answer 22

Rosacea

In patients with rosacea, exercise, ambient heat or cold, spicy foods, alcohol, and hot beverages are common triggers for flushing. Topical cinnamic aldehyde can induce flushing.

Question 23

Drugs associated with flushing

Answer 23

niacin, hormonal agents, serotonin agonists, calcium channel blockers, cyclosporine, chemotherapeutic agents, antimicrobials (vancomycin, metronidazole, rifampin), disulfiram, bromocriptine, intravenous contrast material, vasodilators (nicotinic acid, nitroglycerine, sildenafil and related drugs), and glucocorticoids.

Question 24

Define eryhthema

Answer 24

The term erythema means blanchable redness (hyperemia) of the skin.

Erythema Palmare

Erythema palmare, or persistent palmar erythema, is usually most marked on the hypothenar areas and is associated with an elevated level of circulating estrogen. Cirrhosis, hepatic metastases, and pregnancy are common causes. Hereditary palmar erythema (Lane disease) has been rarely reported.

Generalized Erythema

Generalized erythema may be caused by medications, bacterial toxins, or viral infection. It is often uneven in distribution, being most noticeable on the chest, proximal extremities, and face. In general, these reactions are self-limited and resolve when the offending medication is stopped or the associated infection is treated or resolves. Specific exanthems associated with bacterial or viral infections are discussed in Chapters 14 and 19.

Question 25

Erythema Toxicum Neonatorum

Answer 25

Erythema toxicum neonatorum occurs in a quarter to under half of healthy full-term newborns, usually on the second or third day of life. Because it is so common, dermatologists are usually consulted only for the most florid or atypical cases. Characteristically, the broad erythematous flare is much more prominent than the small follicular papule or pustule it surrounds (Fig. 7.1). Lesions involve the face, trunk, and proximal extremities and appear rarely on the soles or palms. There may be confluent erythema on the face. Fever is absent, and the eruption generally disappears by the 10th day. Erythema toxicum must be distinguished from miliaria, bacterial folliculitis, neonatal herpes, and scabies. When the rash is atypical, smears of the pustules demonstrating eosinophils are adequate to confirm the diagnosis. Rarely, a biopsy is required and demonstrates folliculitis containing eosinophils and neutrophils.

Question 26

In 1860 von Hebra first described erythema exudativum multiforme. The original disease described by von Hebra is now called erythema multiforme minor (minus) or herpes simplex–associated erythema multiforme. It is strongly associated with a preceding herpetic infection. When multiple mucous membranes are involved, the lesions are more intense, and fever or arthralgias accompany the eruption, erythema multiforme major (majus) is diagnosed. This is most often caused by Mycoplasma infection. In contrast, StevensJohnson syndrome (SJS) and toxic epidermal necrolysis (TEN) usually represent adverse reactions to medications (see Chapter 6). As treatment and prognosis are related in part to the inciting agent, it is useful to classify **erythema multiforme (EM)** as follows:

Answer 26

* Herpes simplex–associated EM (HAEM) * Erythema multiforme major (most often caused by Mycoplasma; some suggest the term mycoplasma pneumonia-induced rash and mucositis) * Chronic oral EM * Contact dermatitis–induced EM (see Chapter 6) * Radiation-induced EM (see Chapter 6) * Idiopathic

Question 27

**Herpes simplex–associated EM (HAEM) (erythema multiforme minor)**

Answer 27

HAEM (erythema multiforme minor) is a recurrent self-limited disease, usually of young adults, occurring seasonally in the spring and fall, with each episode lasting 1–4 weeks. The individual clinical lesions begin as sharply marginated, erythematous macules, which become raised, edematous papules over 24–48 hours. The lesions may reach several centimeters in diameter. Typically, a ring of erythema forms around the periphery, and centrally the lesions become flatter, more purpuric, and dusky.

Question 28

Three zones of Erythema multiforme Fig. 7.2 Erythema multiforme, target lesions.

Answer 28

This lesion is the classic **“target” or “iris”** lesion with three zones: **central dusky purpura; an elevated, edematous, pale ring; and surrounding macular erythema (Figs. 7.2 and 7.3).** **Fig. 7.3 Erythema multiforme involving dorsal hands and penis.** The central area may be bullous. Typical targets are best observed on the palms and soles. Lesions generally appear symmetrically and acrally, with initial involvement most frequently on the dorsal hands. The dorsal feet, extensor limbs, elbows, knees, palms, and soles typically become involved. In about 10% of patients, more widespread lesions occur on the trunk. The Koebner phenomenon or photoaccentuation may be observed.

Question 29

**Fig. 7.4 Mucosal lesions of erythema multiforme.**

Answer 29

Mucosal involvement occurs in 25% of cases and is usually limited to the oral mucosa. Oral lesions may appear as indurated plaques, target lesions, or erosions (Fig. 7.4). An atypical variant of HAEM has been described in women. It consists of outbreaks of unilateral or segmental papules and plaques that may be few in number or solitary. Lesions may be up to 20 cm in diameter. The plaques are erythematous and evolve to have a dusky center, which desquamates. Subcutaneous nodules resembling erythema nodosum may be simultaneously present. Histologic examination shows features of EM, and herpes simplex virus (HSV) DNA may be identified in the lesions by polymerase chain reaction (PCR). Acyclovir suppression prevents the lesions. Erythema multiforme major is frequently accompanied by a febrile prodrome and sometimes arthralgias. It occurs in all ages, is centered on the extremities and face, but more often than EM minor may include truncal lesions, which are papular and erythematous to dusky in color. Mucous membrane disease is prominent and often severely involves the oral mucosa and lips with hemorrhagic sloughing; less commonly the genital and ocular mucosa may be involved as well (Fig. 7.5). **Fig. 7.5 Ocular erythema multiforme.**

Question 30

How is SJS distinguised from EM?

Answer 30

SJS is distinguished morphologically by the presence of purpura or bullae in macular lesions of the trunk (Fig. 7.6). **Fig. 7.6 Stevens-Johnson syndrome.** In children, polycyclic urticarial lesions often become dusky centrally and are frequently misdiagnosed as EM. This presentation of urticaria has been dubbed “urticaria multiforme.” It represents urticaria, and histologic changes of EM are never present.