ICD-9: 708.0 ○ ICD-10: L50
Urticaria is composed of wheals (transient edematous papules and plaques, usually pruritic and due to edema of the papillary body) (Fig. 14-6; also see Fig. 14-8). The wheals are superficial, well defined.
Angioedema is a larger edematous area that involves the dermis and subcutaneous tissue (Fig. 14-7) and is deep and ill defined. Urticaria and angioedema are thus the same edematous process but involving different levels of the cutaneous vascular plexus: papillary and deep.
Urticaria and/or angioedema may be acute recurrent or chronic recurrent.
Other forms of urticaria/angioedema are recognized: IgE and IgE receptor dependent, physical, contact, mast cell degranulation related, and idiopathic.
In addition, angioedema/urticaria can be mediated by bradykinin, the complement system, and other effector mechanisms.
Urticarial vasculitis is a special form of cutaneous necrotizing venulitis (see Urticarial Vasculitis).
There are some syndromes with angioedema in which urticarial wheals are rarely present (e.g., hereditary angioedema).
Acute urticaria Small and large wheals with erythematous borders and a lighter color centrally. Well defined. The lesion on the left upper arm is ill defined at its lower border where it is regressing.
Acute urticaria and angioedema Note that there are both superficial wheals and deep, diffuse edema. Occurred after the patient had eaten shellfish. He had similar episodes previously but never considered seafood as the cause.
Epidemiology and Etiology
15–23% of the population may have had this condition during their lifetime.
Urticaria/angioedema is not a disease but a cutaneous reaction pattern. For classification and etiology, see Table 14-1.
TABLE 14-1ETIOLOGY AND CLASSIFICATION OF URTICARIA/ANGIOEDEMA |Favorite Table|Download (.pdf) TABLE 14-1 ETIOLOGY AND CLASSIFICATION OF URTICARIA/ANGIOEDEMA
|Urticaria due to mast cell–releasing agents, pseudoallergens, ACE inhibitors |
|Idiopathic urticaria |
|Nonimmune contact urticaria |
|Urticaria associated with vascular/connective tissue autoimmune disease |
|Distinct angioedema (± urticaria) syndromes |
Acute onset and recurring over <30 days. Usually large wheals often associated with angioedema (Figs. 14-6 and 14-7); often IgE dependent with atopic diathesis; related to foods, parasites, and penicillin. Also, complement mediated in serum sickness–like reactions (whole blood, immunoglobulins, penicillin). Often accompanied by angioedema. Common. (See also “Drug-Induced Acute Urticaria” in Section 23.)
Recurring over <30 days. Small and large wheals (Fig. 14-8). Rarely IgE dependent but often due to anti-FcεR autoantibodies; etiology unknown in 80% and therefore considered idiopathic. Intolerance to salicylates, benzoates. Common. Chronic urticaria affects adults predominantly and is approximately twice as common in women as in men. Up to 40% of patients with chronic urticaria of >6 months’ duration still have urticaria 10 years later.
Chronic urticaria Chronic urticaria of 5-year duration in an otherwise healthy 35-year-old female. Eruptions occur on an almost daily basis and, as they are highly pruritic, greatly impair the patient’s quality of life. Although suppressed by antihistamines, there is an immediate recurrence after treatment is stopped. Repeated laboratory and clinical examinations have not revealed an apparent cause.
Pruritus. In angioedema of palms and soles pain. Angioedema of tongue, pharynx interferes with speech, food intake, and breathing. Angioedema of larynx may lead to asphyxia.
Sharply defined wheals (Fig. 14-6), small (<1 cm) to large (>8 cm), erythematous or white with an erythematous rim, round, oval, acriform, annular, serpiginous (Figs. 14-6 and 14-8), due to confluence and resolution in one area and progression in another (Fig. 14-8). Lesions are pruritic and transient.
Angioedema—skin colored, transient enlargement of portion of face (eyelids, lips, tongue) (Figs. 14-7 and 23-5), extremity, or other sites due to subcutaneous edema.
Distribution. Usually regional or generalized. Localized in solar, pressure, vibration, and cold urticaria/angioedema and confined to the site of the trigger mechanism (see below).
Special Features/As Related to Pathogenesis
IgE Mediated. Lesions in acute IgE-mediated urticaria result from antigen-induced release of biologically active molecules from mast cells or basophilic leukocytes sensitized with specific IgE antibodies (type I anaphylactic hypersensitivity). Released mediators increase venular permeability and modulate the release of biologically active molecules from other cell types. Often with atopic background. Antigens: food (milk, eggs, wheat, shellfish, nuts), therapeutic agents, drugs (penicillin) (see also “Drug-Induced Acute Urticaria, Angioedema, Edema, and Anaphylaxis” in Section 23), helminths. Most often acute (Figs. 14-6 and 23-5).
Complement Mediated. Acute. By way of immune complexes activating complement and releasing anaphylatoxins that induce mast cell degranulation. Serum sickness, administration of whole blood, immunoglobulins.
Autoimmune. Common, chronic. Autoantibodies against FcεRI and/or IgE. Positive autologous serum skin test. Clinically, patients with these autoantibodies (up to 40% of patients with chronic urticaria) are indistinguishable from those without them (Fig. 14-8). These autoantibodies may explain why plasmapheresis, intravenous immunoglobulins, and cyclosporine induce remission of disease activity in these patients.
Immunologic Contact Urticaria. Usually in children with atopic dermatitis sensitized to environmental allergens (grass, animals) or individuals sensitized to wearing latex rubber gloves; can be accompanied by anaphylaxis.
Dermographism. Linear urticarial lesions occur after stroking or scratching the skin; they itch and fade in 30 min (Fig. 14-9); 4.2% of the normal population have it; symptomatic dermographism is a nuisance.
Urticaria: dermographism Urticaria as it appeared 5 min after the patient was scratched on the back. The patient had experienced generalized pruritus for several months with no spontaneously occurring urticaria.
Cold Urticaria. Usually in children or young adults; urticarial lesions confined to sites exposed to cold occurring within minutes after rewarming. “Ice cube” test (application of an ice cube for a few minutes to skin) causes wheal.
Solar Urticaria. Urticaria after solar exposure. Action spectrum from 290 to 500 nm; whealing lasts for <1 h, may be accompanied by syncope; histamine is one of the mediators (see Section 10 and Fig. 10-11).
Cholinergic Urticaria. Exercise to the point of sweating provokes typical small, papular, highly pruritic urticarial lesions (Fig. 14-10). May be accompanied by wheezing.
Cholinergic urticaria Small urticarial papules on neck occurring within 30 min of vigorous exercise. Papular urticarial lesions are best seen under side lighting.
Aquagenic Urticaria. Very rare. Contact with water of any temperature induces eruption similar to cholinergic urticaria.
Pressure Angioedema. Erythematous swelling induced by sustained pressure (buttock swelling when seated, hand swelling after hammering, foot swelling after walking). Delayed (30 min to 12 h). Painful, may persist for several days, and interferes with quality of life. No laboratory abnormalities; fever may occur.
Vibration Angioedema. May be familial (autosomal dominant) or sporadic. Rare. It is believed to result from histamine release from mast cells caused by a “vibrating” stimulus—rubbing a towel across the back produces lesions, but direct pressure (without movements) does not.
Urticaria Due to Mast Cell–Releasing Agents and Pseudoallergens and Chronic Idiopathic Urticaria
Urticaria/angioedema and even anaphylaxis-like symptoms may occur with radiocontrast media and as a consequence of intolerance to salicylates, food preservatives and additives (e.g., benzoic acid and sodium benzoate), several azo dyes, including tartrazine and sunset yellow (pseudoallergens) (Fig. 14-8); also to ACE inhibitors. May be acute and chronic. In chronic idiopathic urticaria, histamine derived from mast cells in the skin is considered the major mediator, also eicosanoids and neuropeptides.
Nonimmune Contact Urticaria. Due to direct effects of exogenous urticants penetrating into skin or blood vessels. Localized to site of contact. Sorbic acid, benzoic acid in eye solutions and foods, cinnamic aldehydes in cosmetics, histamine, acetylcholine, serotonin in nettle stings.
Urticaria Associated with Vascular/Connective Tissue Autoimmune Disease
Urticarial lesions may be associated with systemic lupus erythematosus (SLE) and Sjögren syndrome. However, in most instances, they represent urticarial vasculitis (see Urticarial Vasculitis).
Distinct Angioedema (〿 Urticaria) Syndromes. Hereditary Angioedema (HAE)
A serious autosomal-dominant disorder; may follow trauma (physical and emotional). Angioedema of the face (Fig. 14-11) and extremities, episodes of laryngeal edema, and acute abdominal pain caused by angioedema of the bowel wall presenting as surgical emergency. Urticaria rarely occurs. Laboratory abnormalities involve the complement system: decreased levels of C1-esterase inhibitor (85%) or dysfunctional inhibitor (15%), low C4 value in the presence of normal C1 and C3 levels. Angioedema results from bradykinin formation, since C1-esterase inhibitor is also the major inhibitor of the Hageman factor and kallikrein, the two enzymes required for kinin formation. Episodes can be life threatening.
Hereditary angioedema (A) Severe edema of the face during an episode leading to grotesque disfigurement. (B) Angioedema will subside within hours. These are the normal features of the patient. The patient had a positive family history and had multiple similar episodes including colicky abdominal pain.
Angioedema–Urticaria–Eosinophilia Syndrome. Severe angioedema, only occasionally with pruritic urticaria, involving the face, neck, extremities, and trunk that lasts for 7–10 days. There is fever and marked increase in normal weight (increased by 10–18%) owing to fluid retention. No other organs are involved. Laboratory abnormalities include striking leukocytosis (20,000–70,000/μL) and eosinophilia (60–80% eosinophils), which are related to the severity of attack. There is no family history. This condition is rare, prognosis is good.
Search for hepatitis B–associated antigen, assessment of the complement system, assessment of specific IgE antibodies by radioallergosorbent test (RAST), anti-FcεRI autoantibodies. Serology for lupus and Sjögren syndrome. Autologous serum skin test for autoimmune urticaria.
The erythrocyte sedimentation rate (ESR) is often elevated in urticarial vasculitis, and there may be hypocomplementemia; transient eosinophilia in urticaria from reactions to foods, parasites, and drugs; high levels of eosinophilia in the angioedema–urticaria–eosinophilia syndrome.
Screening for functional C1 inhibitor in HAE.
For early diagnosis of bowel involvement in HAE; if abdominal pain is present, this may indicate edema of the bowel.
Stool specimen for presence of parasites.
A detailed history (previous diseases, drugs, foods, parasites, physical exertion, solar exposure) is of utmost importance. History should differentiate between type of lesions—urticaria, angioedema, or urticaria + angioedema; duration of lesions (<1 h or ≥1 h), pruritus; pain on walking (in foot involvement), flushing, burning, and wheezing (in cholinergic urticaria). Fever in serum sickness and in the angioedema–urticaria–eosinophilia syndrome; in angioedema, hoarseness, stridor, dyspnea. Arthralgia (serum sickness, urticarial vasculitis), abdominal colicky pain in HAE. A careful history of medications including penicillin, aspirin, nonsteroidal anti-inflammatory drugs, and ACE inhibitors should be obtained.
Dermographism is evoked by stroking the skin; pressure urticaria is tested by application of pressure (weight) perpendicular to the skin; vibration angioedema by a vibratory stimulus, like rubbing the back with a towel. Cholinergic urticaria can best be diagnosed by exercise to sweating and intracutaneous injection of acetylcholine or mecholyl, which will produce micropapular whealing. Solar urticaria is verified by testing with UVB, UVA, and visible light (see Fig. 10-11). Cold urticaria is verified by a wheal response to the application to the skin of an ice cube or a test tube containing ice water. Autoimmune urticaria is tested by the autologous serum skin test and determination of anti-FcεRI antibody. If urticarial wheals do not disappear in ≤24 h, urticarial vasculitis should be suspected and a biopsy done. The person with angioedema–urticaria–eosinophilia syndrome has high fever, high leukocytosis (mostly eosinophils), a striking increase in body weight due to retention of water, and a cyclic pattern that may occur and recur over a period of years. HAE has a positive family history and is characterized by angioedema as the result of trauma, abdominal pain, and decreased levels of C4 and C1-esterase inhibitor.
A practical approach to the diagnosis of urticaria/angioedema is shown in Fig. 14-12 and to angioedema alone in Fig. 14-13.
Approach to the patient with urticaria/angioedema. [Modified from Kaplan AP, in Wolff K et al. (eds.): Fitzpatrick’s Dermatology in General Medicine, 7th ed. New York, McGraw-Hill, 2008:339.]
Approach to the patient with angioedema (without urticaria). [Modified from Kaplan AP, in Wolff K et al. (eds.): Fitzpatrick’s Dermatology in General Medicine, 7th ed. New York, McGraw-Hill, 2008:339.]
Half of the patients with urticaria alone are free of lesions in 1 year, but 20% have lesions for >20 years. Prognosis is good in most syndromes except HAE, which may be fatal if untreated.
Prevention by elimination of etiologic chemicals or drugs: aspirin and food additives, especially in chronic recurrent urticaria—rarely successful; prevent trigger in physical urticarias.
H1-blockers, e.g., hydroxyzine, terfenadine; or loratadine, cetirizine, fexofenadine; 180 mg/d of fexofenadine or 10–20 mg/d of loratadine usually controls most cases of chronic urticaria, but cessation of therapy usually results in a recurrence; if they fail, H1 and H2 blockers (cimetidine) and/or mast cell–stabilizing agents (ketotifen). Doxepin, a tricyclic antidepressant with marked H1 antihistaminic activity, is valuable when severe urticaria is associated with anxiety and depression.
In acute urticaria with angioedema; also for angioedema–urticaria–eosinophilia syndrome.
Long-term therapy for HAE; watch out for hirsutism, irregular menses; whole fresh plasma or C1-esterase inhibitor in the acute attack. A very effective bradikin-B2-receptor antagonist for subcutaneous application is now available in Europe (Icatibant).
In chronic idiopathic or autoimmune urticaria, if no response to antihistamines: switch to cyclosporine and taper gradually, if glucocorticoids are contraindicated or if side effects occur.
Erythema Multiforme (EM) Syndrome
ICD-9: 695.1 ○ ICD-10: L51
A common reaction pattern of blood vessels in the dermis with secondary epidermal changes.
Manifests clinically as characteristic erythematous iris-shaped papular and vesiculobullous lesions.
Typically involving the extremities (especially the palms and soles) and the mucous membranes.
Benign course with frequent recurrences.
Most cases related to herpes simplex virus (HSV) infection.
Recurrences can be prevented by long-term anti-HSV medication.
More severe course in EM major.
More frequent in males than in females.
A cutaneous reaction to a variety of antigenic stimuli, most commonly to herpes simplex.
Herpes simplex, Mycoplasma.
Sulfonamides, phenytoin, barbiturates, phenylbutazone, penicillin, allopurinol.
Probably also due to undetected herpes simplex or Mycoplasma.
Evolution of lesions over several days. May have history of prior EM. May be pruritic or painful, particularly mouth lesions. In severe forms constitutional symptoms such as fever, weakness, malaise.
Lesions may develop over ≥10 days. Macule → papule (1–2 cm) → vesicles and bullae in the center of the papule. Dull red. Iris or target-like lesions result and are typical (Figs. 14-14 and 14-15). Localized to hands and face or generalized (Figs. 14-16 and 14-17). Bilateral and often symmetric.
Erythema multiforme Iris or target lesions on the palm of a 16-year-old. The lesions are very flat papules with a red rim, a violaceous ring, and a red center.
Erythema multiforme: minor Multiple, confluent, target-like papules on the face of a 12-year-old boy. The target morphology of the lesions is best seen on the lips.
Erythema multiforme: major Erythematous, confluent, target-like papules, erosions and crusts on the face. There is erosive and crusted cheilitis indicating mucosal involvement, and there is conjunctivitis. The patient also had a generalized rash consisting of iris lesions.
Erythema multiforme: major Multiple, target lesions have coalesced, and erosions will develop. This patient had fever and mucosal involvement of mouth, conjunctiva, and genitalia.
Sites of Predilection. Dorsa of hands, palms, and soles; forearms; feet; face; elbows and knees; penis (50%) and vulva (see Fig. 14-18).
Erythema multiforme predilection sites and distribution.
Erosions with fibrin membranes; occasionally ulcerations: lips (Fig. 14-15, see also Section 33), oropharynx, nasal, conjunctival (Fig. 14-16), vulvar, anal.
Eyes, with corneal ulcers, anterior uveitis.
Little or no mucous membrane involvement; vesicles but no bullae or systemic symptoms. Eruption usually confined to extremities, face, classic target lesions (Figs. 14-14 and 14-15). Recurrent EM minor is usually associated with an outbreak of herpes simplex preceding it by several days.
Most often occurs as a drug reaction, always with mucous membrane involvement; severe, extensive, tendency to become confluent and bullous, positive Nikolsky sign in erythematous lesions (Figs. 14-16 and 14-17). Systemic symptoms: fever, prostration. Cheilitis and stomatitis interfere with eating; vulvitis and balanitis with micturition. Conjunctivitis can lead to keratitis and ulceration; lesions also in pharynx and larynx.
Inflammation characterized by perivascular mononuclear infiltrate, edema of the upper dermis; apoptosis of keratinocytes with focal epidermal necrosis and subepidermal bulla formation. In severe cases, complete necrosis of epidermis as in toxic epidermal necrolysis. (See Section 8.)
Diagnosis and Differential Diagnosis
The target-like lesion and the symmetry are quite typical, and the diagnosis is not difficult.
Acute Exanthematic Eruptions
Drug eruption, psoriasis, secondary syphilis, urticaria, generalized Sweet syndrome. Mucous membrane lesions may present a difficult differential diagnosis: bullous diseases, fixed drug eruption, acute lupus erythematosus, primary herpetic gingivostomatitis.
Control of herpes simplex using oral valaciclovir or famciclovir may prevent development of recurrent EM.
In severely ill patients, systemic glucocorticoids are usually given (prednisone, 50–80 mg/d in divided doses, quickly tapered), but their effectiveness has not been established by controlled studies.
Are rare systemic autoinflammatory diseases, autosomal dominant.*
Include familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) (Fig. 14-19) and neonatal-onset multisystem inflammatory disease (NOMID).
Most have mutations in NLRP3.
Urticaria-like eruptions (Fig. 14-19), fever (periodic or continuous), conjunctivitis, arthralgia and elevation of acute phase reactants. Untreated develop progressive hearing loss, progressive vision loss (MWS, NOMID), mental retardation, hydrocephalus, bony overgrowth (NOMID) and amyloidosis.
Histopathology of lesional skin shows edema, dilatation of superficial capillaries, perivascular and perieccrine neutrophilic infiltrates.
Anti-IL-1 therapy is effective.
Muckle-Wells syndrome in a 2-month-old baby with fever and arthralgia and an urticarial rash. (Courtesy of Drs. Klemens Rappersberger and Christian Posch.)
ICD-9: 697.0 ○ ICD-10: L43
Worldwide occurrence; incidence less than 1%, all races.
LP is an acute or chronic inflammatory dermatosis involving skin and/or mucous membranes.
Characterized by flat-topped (Latin planus, “flat”), pink to violaceous, shiny, pruritic polygonal papules. The features of the lesions have been designated as the four P’s—papule, purple, polygonal, pruritic.
Distribution: predilection for flexural aspects of arms and legs, can become generalized.
In the mouth, milky-white reticulated papules; may become erosive and even ulcerate.
Main symptom: pruritus; in the mouth, pain.
Therapy: topical and systemic glucocorticoids, cyclosporine.
Epidemiology and Etiology
Idiopathic in most cases but cell-mediated immunity plays a major role. Majority of lymphocytes in the infiltrate are CD8+ and CD45Ro+ (memory) cells. Drugs, metals (gold, mercury), or infection (hepatitis C virus) result in alteration in cell-mediated immunity. There could be HLA-associated genetic susceptibility that would explain a predisposition in certain persons. Lichenoid lesions of chronic graft-versus-host disease (GVHD) of skin are indistinguishable from those of LP (see Section 22).
Acute (days) or insidious (over weeks). Lesions last months to years, asymptomatic or pruritic; sometimes severe pruritus. Mucous membrane lesions are painful, especially when ulcerated.
Papules, flat-topped, 1–10 mm, sharply defined, shiny (Fig. 14-20). Violaceous, with white lines (Wickham striae) (Fig. 14-20A), seen best with hand lens after application of mineral oil. Polygonal or oval (Fig. 14-20B). Grouped (Figs. 14-20 and 14-21), annular, or disseminated scattered discrete lesions when generalized (Fig. 14-22). In dark-skinned individuals, postinflammatory hyperpigmentation is common. May present on lips (Fig. 14-23A) and in a linear arrangement after trauma (Koebner or isomorphic phenomenon (Fig. 14-23B).
Lichen planus (A) Flat-topped, polygonal, sharply defined papules of violaceous color, grouped and confluent. Surface is shiny and, upon close inspection with a hand lens, fine white lines are revealed (Wickham striae, arrow). (B) Close up of flat-topped shiny violaceous papules that are polygonal.
Hypertrophic lichen planus (A) Confluent hyperkeratotic papules and plaques on the dorsum of the hand of a light-colored man of African descent. Hyperkeratosis covers Wickham striae, and the characteristic violaceous color of the lesions can be seen only at the very margins. (B) Hypertrophic lichen planus on the dorsum of the foot. Lesions form thick plaques with a hyperkeratotic surface and a violaceous border.
Disseminated lichen planus A shower of disseminated papules on the trunk and the extremities (not shown) in a 45-year-old Filipino. Due to the ethnic color of the skin, the papules are not as violaceous as in Caucasians but have a brownish hue.
Lichen planus (A) Silvery-white, confluent, flat-topped papules on the lips. Note: Wickham striae (arrow). (B) Lichen planus, Koebner phenomenon. Linear arrangement of flat-topped, shiny papules that erupted after scratching.
Sites of Predilection. Wrists (flexor), lumbar region, shins (thicker, hyperkeratotic lesions; Fig. 14-21B), scalp, glans penis (see Section 36), mouth (see Section 35).
Large thick plaques arise on the foot (Fig. 14-21B), dorsum of hands (Fig. 14-21A), and shins; more common in black males. Although typical LP papule is smooth, hypertrophic lesions may become hyperkeratotic.
Atrophic. White-bluish, well-demarcated papules and plaques with central atrophy.
Follicular. Individual keratotic-follicular papules and plaques that lead to cicatricial alopecia. Spinous follicular lesions, typical skin and mucous membrane LP, and cicatricial alopecia of the scalp are called Graham Little syndrome (see Section 33).
Vesicular. Vesicular or bullous lesions may develop within LP patches or independent of them within normal-appearing skin. There are direct immunofluorescence findings consistent with bullous pemphigoid, and the sera of these patients contain bullous pemphigoid IgG autoantibodies (see Section 6).
Pigmentosus. Hyperpigmented, dark-brown macules in sun-exposed areas and flexural folds. In Latin Americans and other dark-skinned populations. Significant similarity or perhaps identity with ashy dermatosis (see Fig. 13-12).
Actinicus. Papular LP lesions arise in sun-exposed sites, especially the dorsa of hands and arms.
Ulcerative. LP may lead to therapy-resistant ulcers, particularly on the soles, requiring skin grafting.
Some 40–60% of individuals with LP have oropharyngeal involvement (see Section 33).
Reticular LP. Reticulate (netlike) pattern of lacy white hyperkeratosis on buccal mucosa (see Section 35), lips (Fig. 14-23A), tongue, gingiva; the most common pattern of oral LP.
Erosive or Ulcerative LP. Superficial erosion with/without overlying fibrin clot; occurs on tongue and buccal mucosa (see Section 33); shiny red painful erosion of gingiva (desquamative gingivitis) (see Section 33) or lips (Fig. 14-23A). Carcinoma may very rarely develop in mouth lesions.
Papular (see Section 34) agminated, annular, or erosive lesions arise on penis (especially glans), scrotum, labia majora, labia minora, vagina.
Scalp. Follicular LP, atrophic scalp skin with scarring alopecia. (See Section 33.)
Nails. Destruction of nail fold and nail bed with longitudinal splintering (see Section 32).
Lichen Planus–Like Eruptions
LP-like eruptions closely mimic typical LP, both clinically and histologically. They occur as a clinical manifestation of chronic GVHD, in dermatomyositis (DM), and as cutaneous manifestations of malignant lymphoma but may also develop as the result of therapy with certain drugs and after industrial use of certain compounds (see Section 23).
Diagnosis and Differential Diagnosis
Clinical findings confirmed by histopathology.
Papular LP. Chronic cutaneous lupus erythematosus, psoriasis, pityriasis rosea, eczematous dermatitis, lichenoid GVHD; single lesions: superficial basal cell carcinoma, Bowen disease (in situ squamous cell carcinoma).
Hypertrophic LP. Psoriasis vulgaris, lichen simplex chronicus, prurigo nodularis, stasis dermatitis, Kaposi sarcoma.
Leukoplakia, pseudomembranous candidiasis (thrush), HIV-associated hairy leukoplakia, lupus erythematosus, bite trauma, mucous patches of secondary syphilis, pemphigus vulgaris, bullous pemphigoid (see Section 35).
Drug-Induced LP. See Section 23.
Inflammation with hyperkeratosis, increased granular layer, irregular acanthosis, liquefaction degeneration of the basal cell layer, and band-like mononuclear infiltrate that hugs the epidermis. Keratinocyte apoptosis (colloid, Civatte bodies) found at the dermal–epidermal junction. Direct immunofluorescence reveals heavy deposits of fibrin at the junction and IgM and, less frequently, IgA, IgG, and C3 in the colloid bodies.
Cutaneous LP usually persists for months, but in some cases, for years; hypertrophic LP on the shins and oral LP often for decades. The incidence of oral squamous cell carcinoma in individuals with oral LP is increased (5%).
Glucocorticoids. Topical glucocorticoids with occlusion for cutaneous lesions. Intralesional triamcinolone (3 mg/mL) is helpful for symptomatic cutaneous or oral mucosal lesions and lips.
Cyclosporine and Tacrolimus Solutions. Retention “mouthwash” for severely symptomatic oral LP.
Cyclosporine. In very resistant and generalized cases, 5 mg/kg per day will induce rapid remission, quite often not followed by recurrence.
Glucocorticoids. Oral prednisone is effective for individuals with symptomatic pruritus, painful erosions, dysphagia, or cosmetic disfigurement. A short, tapered course is preferred: 70 mg initially, tapered by 5 mg/d.
Systemic Retinoids (Acitretin). 1 mg/kg per day is helpful as adjunctive measure in severe (oral, hypertrophic) cases, but usually additional topical treatment is required.
In individuals with generalized LP or cases resistant to topical therapy.
Mycophenolate mofetil, heparin analogues (enoxaparin) in low doses have antiproliferative and immunomodulatory properties; azathioprine.