DERMATOLOGY Flashcards
a Tzanck showing multinucleated epithelial giant cells?
VARICELLA ZOSTER
Tzanck smear is a cytologic technique most often used in the diagnosis of herpesvirus infections (herpes simplex virus [HSV] or varicella-zoster virus [VZV]). Multinucleated epithelial giant cells suggest the presence of HSV or VZV.
38 year old male developed greasy scales overlying erythematous patches or plaques in the eyebrows, eyelids, glabella, and nasolabial folds, which he described as dandruff. What is the dx? and best management for this case?
Seborrheic dermatitis tx:
reatment with low-potency topical glucocorticoids in conjunction with a topical antifungal agent, such as ketoconazole cream or ciclopirox cream, is often effective. High-potency glucocorticoids should not be used on the face because this treatment is often associated with steroid-induced rosacea or atrophy.
A 68 year old female presented with pruritic, erythematous, curvilinear plaques with scaling on the anterior surface of her both legs. She recently went to Northern Mongolia during the winter season. What is the best management of choice?
Asteatotic eczema, also known as xerotic eczema or “winter itch,” is a mildly inflammatory dermatitis that develops in areas of extremely dry skin, especially during the dry winter months. Asteatotic eczema responds well to topical moisturizers and the avoidance of cutaneous irritants.
What organism causes the lesion shown below which produces the character
Corynebacterium minutissimum
Wood’s lamp will cause erythrasma (a superficial, intertriginous infection caused by Corynebacterium minutissimum) to show a characteristic coral pink color, and wounds colonized by Pseudomonas will appear pale blue.
wounds colonized by _____will appear pale blue under wood’s lamp
wounds colonized by Pseudomonas will appear pale blue.
True re: STASIS DERMATITIS
Diuretics may be required to adequately control chronic edema.
Patients with stasis dermatitis and stasis ulceration benefit greatly from leg elevation and the routine use of compression stockings with a gradient of at least 30–40 mmHg.
The typical initial site of involvement is the** medial **aspect of the ankle…
Glucocorticoids should not be applied to ulcers, because they may retard healing…
All are correct
ALL ARE CORRECT
A 46 year old male came in your clinic due to progressive sharply demarcated intensely erythematous plaques with secondary pustules and scaling, initially started in the palms and soles before progressing to his arms and legs. He also reported undocumented febrile episodes. He recently used an unrecalled topical skin care product recommended by a friend. What is the best management of choice
Diagnosis: pustular psoriasis, patients may have disease localized to the palms and soles, or the disease may be generalized. Regardless of the extent of disease, the skin is erythematous, with pustules and variable scale. When it is generalized, episodes are characterized by fever (39°–40°C [102.2°–104.0°F]) lasting several days, an accompanying generalized eruption of sterile pustules, and a background of intense erythema; patients may become erythrodermic. Local irritants, pregnancy, m tions, infections, and systemic glucocorticoid withdrawal can precipitate this form of psoriasis. Oral retinoids are the treatment of choice in nonpregnant patients.
Drugs that can cause Pityriasis rosea like
Pityriasis rosea–like drug eruptions are seen most commonly with:
* beta blockers,
* angiotensin-converting enzyme (ACE) inhibitors
* metronidazole,
medications that can produce lichenoid eruptions
LICHENOID eruption include:
1. thiazides,
2. antimalarials,
3. quinidine,
4. beta blockers,
5. TNF inhibitors,
6. anti-PD-1/PD-L1 antibodies, and
7. ACE inhibitors.
A 57 year old male presented with opacified and thickened nails and subungual debris. He has hypertension, heart failure, and was recently diagnosed with HIV. Which medications is appropriate for this patient?
TERBINAFINE
Two other oral antifungal agents, itraconazole and terbinafine, are sometimes prescribed “off-label” for superficial fungal infections. Oral itraconazole is approved for onychomycosis. Itraconazole has the potential for serious interactions with other drugs requiring the P450 enzyme system for metabolism. Itraconazole should not be administered to patients with evidence of ventricular dysfunction or patients with known CHF.
most common malignancy that is associated with acanthosis nigricans
GASTRIC
Acanthosis nigricans can be a reflection of an internal malignancy, most commonly of the gastrointestinal tract, and it appears as velvety hyperpigmentation, primarily in flexural areas.
What is the most common manifestation of patients with Dermatomyositis
The most common manifestation is a purple-red discoloration of the upper eyelids, sometimes associated with scaling (“heliotrope” erythema; Fig. 59-3) and periorbital edema.
CLinical feautures of genital ulcers
Nonscarring alopecia (primary cutaneous disorders)
key pathway in the pathophysiology of adverse drug reaction in contact dermatitis
the key pathway of ADE in contact dermatitis is T-lymphocyte-mediated macrophage inflammation
A 40 year old male initially presented with cough and fever, and was given Cotrimoxazole by a local physician. He eventually developed high grade fever, sore throat, conjunctivitis, oral ulcerations, and acute onset of painful dusky, atypical, target-like lesions of hands and feet, eventually progressing of abdomen and bilateral legs with 40% desquamation. What is the best management for this case
Dx: TEN
The case presented is a case of toxic epidermal necrolysis (TEN). At this time, there is no consensus on the most effective treatment for SJS/TEN. The best outcomes stem from early diagnosis, immediate discontinuation of the suspected drug, and meticulous supportive therapy in an intensive care or burn unit. Early administration of systemic glucocorticoids, intravenous immunoglobulin, cyclosporine, or etanercept may improve disease outcomes, but randomized studies to evaluate potential therapies are lacking and difficult to perform.
26 year old female patient comes to your clinic for skin eruptions characterized by multiple erythematous plaques with a target morphology, treated for UTI a few days prior given TMPSMX
The patient has erythema multiforme. This eruption is characterized by multiple erythematous plaques with a target or iris morphology. It usually represents a hypersensitivity reaction to drugs (e.g., sulfonamides) or infections (e.g., HSV).
True or falseCyclosporine P 378 UV-light therapy is contraindicated in patients receiving cyclosporine as patients on cyclosporine has an increased risk of developing skin cancer when exposed to phototherapy
:
TRUE OR FALSE
Cyclosporine P 378 UV-light therapy is contraindicated in patients receiving cyclosporine as patients on cyclosporine has an increased risk of developing skin cancer when exposed to phototherapy
TRUE
large >2cm FLAT lesion with a color diff from the surrounding skin
PATCH
primary skin lesion described as a large (0.5-5.0 cm) firm lesion raised above the surface of the surrounding skin:
Nodule
a flat colored lesion <2cm not raised above the surrounding skin
MACULE
solid raised growth >5cm in diameter
TUMOR
large >1cm flat topped raised may either be distinct
Plaque
seen in Psoriasis, eczematous dermatitis
small lesion solid, <0.4 cm in diameter RAISED above the surface
Papule
(seen in closed comedone, acne, headache)
small fluid lesion less than 0.5 cm in diameter, raised above the plane of surrounding skin
vesicle
vesicle filled with leucocytes
PUSTULES
a fluid filled, rased often translucent lesion 0.5cm in diameter
BULLA
raised, eryhtematous edematous papule or plaque, representing short lived VASO DILATION AND PERMEABILITY
WHEAL
violacious to purple
polygonal lesions
Lichenoid eruption
oval to round plaques with trailing scale, eruption lines up in skinfolds
Pityriasis rosea
sharply dermacated, plaques, on knees, elbows, scalps, intertirginous areas
psoriasis
purple polygonal papules marked by severe pruritus, lacy white markings, especially associated with mucous membrane lesions
Lichen planus
Polymorphous appearance, sharply deifined to ill demarcated scaly plaques, may be associated with hair loss
Dermatophytosis
benign proliferations of nevomelanocytes characterized by regularly shaped hyperpigmented macules or papules of a uniform color
FIGURE 56-2 Nevomelanocytic nevus. Nevi are benign proliferations of nevomelanocytes characterized by regularly shaped hyperpigmented macules or papules of a uniform color.
FIGURE 56-1 Superficial spreading melanoma. This is the most common type of melanoma. Such lesions usually demonstrate asymmetry, border irregularity, color variegation (black, blue, brown, pink, and white), a diameter >6 mm, and a history of change (e.g., an increase in size or development of associated symptoms such as pruritus or pain).
secondary lesion- distincitive thickening of the skin
secondary lesions?
Lichenification
Scale
Crust
Erosion
Ulcer
Excoriation
Atrophy
Chalk-white macules, in Periorificial, trunk, extensor surfaces of extremities, flexor wrists, axillae
Vitiligo
Indurated and possibly hyperkeratotic lesions often showing ulceration and/or crusting
squamous cell carcinoma
Papule with pearly, telangiectatic border on
sun-damaged skin
basal cell carcinoma
Trunk (Christmas tree pattern); herald patch followed by multiple smaller lesions
Symmetric erythematous papules and plaques with a collarette of scale
Pityriasis rosea
Dermatomal, usually trunk but may be anywhere
vesicles
HSV
scaly hyper- or hypopigmented macules in chest back abdomen, proximal extremities
Tinea versicolor
Brown plaques with adherent, greasy scale; “stuck on” appearance
Seborrheic keratosis
Follicular pustules
Papules, vesicles, pustules, often with **honey-colored crusts **in any hair bearing area, can occur anywhere as well
Folliculitis Impetigo
Patches of erythema and scaling on background of hyperpigmentation associated with signs of venous insufficiency, ankles lower legs over MEDIAL Malleoli
Stasis dermatitis
Palpable purpuric papules on the lower legs are seen in this patient with cutaneous small-vessel vasculitis.
Necrotizing vasculitis. Palpable purpuric papules on the lower legs are seen in this patient with cutaneous small-vessel vasculitis. (Courtesy of Robert Swerlick, MD; with permission.)
Meningococcemia. An example of fulminant meningococcemia with extensive angular purpuric patches.
This papulosquamous skin disease is characterized by small and large erythematous papules and plaques with overlying adherent silvery scale.
Psoriasis
Pathophysiology
Autoimmune Mechanism
Dysregulated T-cell mediated immune response (Th1, Th17 pathways).
IL-23/IL-17 axis plays a major role.
Overproduction of TNF-α, IL-17, IL-22, and IL-23 drives inflammation.
Keratinocyte Hyperproliferation
Abnormal differentiation and proliferation of keratinocytes, leading to thickened epidermis (acanthosis), parakeratosis (retention of nuclei in stratum corneum), and elongated rete ridges.
Angiogenesis & Inflammation
Increased vascularization in the dermis due to VEGF activation.
Discrete and confluent, edematous, erythematous papules and plaques are characteristic of this whealing eruption
urticaria
ERYTHEMA MULTIFORMEThis eruption is characterized by multiple erythematous plaques with a target or iris morphology. It usually represents a hypersensitivity reaction to drugs (e.g., sulfonamides) or infections (e.g., HSV).
a cytologic technique most often used in the diagnosis of herpesvirus infections (herpes simplex virus [HSV] or varicella-zoster virus [VZV])- placed on a glass slide, air-dried, and stained with Giemsa or Wright’s stain. Multinucleated epithelial giant cells suggest the presence of HSV or VZV; culture, immunofluorescence microscopy, or genetic testing must be performed to identify the specific virus
A Tzanck smear is a cytologic technique most often used in the diagnosis of herpesvirus infections (herpes simplex virus [HSV] or varicella-zoster virus [VZV])
Vitiligo
Characteristic lesions display an acral distribution and striking depigmentation as a result of loss of melanocytes.
Diagnosis?
1. Pruritus and scratching
2. Course marked by exacerbations and remissions
3. Lesions typical of eczematous dermatitis
4. Personal or family history of atopy (asthma, allergic rhinitis, food allergies, or eczema)
5. Clinical course lasting >6 weeks
6. Lichenification of skin
7. Presence of dry skin
atopic dermatitis
characterized by circular or oval “coinlike” lesions, beginning as small edematous papules that become crusted and scaly in thr trunk, extensor surfaces
Nummular eczema is characterized by circular or oval “coinlike” lesions, beginning as small edematous papules that become crusted and scaly. The etiology of nummular eczema is unknown, but dry skin is a contributing factor. Common locations are the trunk or the extensor surfaces of the extremities, particularly on the pretibial areas or dorsum of the hands. Nummular eczema occurs more frequently in men and is most common in middle age. The treatment of nummular eczema is similar to that for AD.
deep-seated vesicles and scaling on palms and lateral fingers, and the disease is often associated with an atopic diathesis.
Dyshidrotic eczema. This example is characterized by deep-seated vesicles and scaling on palms and lateral fingers, and the disease is often associated with an atopic diathesis.
Stasis dermatitis. An example of stasis dermatitis showing erythematous, scaly, and oozing patches over the lower leg. Several stasis ulcers are also seen in this patient.
. Central facial erythema with overlying greasy, yellowish scale is seen in this patient.
Seborrheic dermatitis. Central facial erythema with overlying greasy, yellowish scale is seen in this patient.
Tx:
Treatment with low-potency topical glucocorticoids in conjunc- tion with a topical antifungal agent, such as ketoconazole cream or ciclopirox cream, is often effective. The scalp and beard areas may benefit from antidandruff shampoos, which should be left in place 3–5 min before rinsing. High-potency topical glucocorticoid solutions (betamethasone or clobetasol) are effective for control of severe scalp involvement. High-potency glucocorticoids should not be used on the face because this treatment is often associated with steroid-induced rosacea or atrophy.
Type of psoriasis that is most common in children and young adults. It develops acutely in individuals without psoriasis or in those with chronic plaque psoriasis. Patients present with many small erythematous, scaling papules, frequently after upper respiratory tract infection with β-hemolytic streptococci.* The differential diagno- sis should include pityriasis rosea and secondary syphilis.*
Guttate psoriasis (eruptive psoriasis)
FDA Approved therapy for psoriasis
side effects(Renal dysfunction, hypertension, hyperkalemia, hyperuricemia, hypomagnesemia, hyperlipidemia, increased risk of malignancies) of what psoriasis drug ?
Cyclosporine
calcineurin inhibitor
PDE4 inhibitor fda approved for Psoriasis
Apremilast
Adverse effects of Methortrexate
Hepatotoxicity, pulmonary toxicity, pancytopenia, potential for increased malignancies, ulcerative stomatitis, nausea, diarrhea, teratogenicity
FDA Approved Biologics for Psoriasis or Psoriatic Arthritis
psoriasis medications that work via Anti-TNF-α
Etanercept (Ps, PsA; SC) Adalimumab (Ps, PsA; SC) Certolizumab (Ps, PsA; SC) Infliximab (Ps, PsA; IV)
Golimumab (PsA; SC)
showing multiple flat- topped, violaceous papules and plaques. Nail dystrophy, as seen in this patient’s thumbnail, may also be a feature.
Lichen planus
anti IL 12 and IL 23
treatment for psoriasis
Ustekinumab
Anti-IL-23 treatment for psoriasis
RISA TILDRA GUSEL 23
Risankizumab (Ps; SC) Tildrakizumab (Ps; SC) Guselkumab (
multiple round to oval erythematous patches with fine central scale are distributed along the skin tension lines on the trunk,
Pityriasis rosea.
papulosquamous eruption of unknown eti- ology occurring more commonly in the spring and fall. Its first mani- festation is the development of a 2- to 6-cm annular lesion (the herald patch). This is followed in a few days to a few weeks by the appearance of many smaller annular or papular lesions with a predilection to occur on the trunk
Anti-IL-17
SE-XE-BRODA == 17
Secukinumab (Ps, PsA; SC) Ixekizumab (Ps; SC)
Brodalumab (Ps; SC)
with inflammatory papules, pustules, and comedones. (
acne vulgaris
Treatment of acne vulgaris is directed toward elimination of come- dones by normalizing follicular keratinization and decreasing seba- ceous gland activity, the population of C. acnes, and inflammation
Erythroderma Figure
Prominent facial erythema, telangiectasia, scattered papules, and small pustules are seen in this patient with acne rosacea.
tx: Acne rosacea can be treated topically or systemically. Mild disease often responds to topical preparations of metronidazole, sodium sulfacetamide, azelaic acid, ivermectin, brimonidine, or oxyme- tazoline. More severe disease requires oral tetracyclines in suban- timicrobial, modified-release preparations. Residual telangiectasia may respond to laser therapy. Topical glucocorticoids, especially potent agents, should be avoided because chronic use of these prep- arations may elicit rosacea. Application of topical agents to the skin is not effective treatment for ocular disease.
non-scarring alopecia causes
Tx for Upper trunk and neck (shawl- like distribution), groin
Young adults
Macules have fine white scale when scratched
with golden flouroscense, on wood’s lamp
skin biopsy: hyphal forms and budding yeast in stratum corneum
Pityriasis (tinea) versicolora
Tx? Selenium sulfide 2.5% shampoo; topical imidazoles; oral triazoles
Pathogenesis:
Invasion of stratum corneum by the yeast Malassezia
Yeast is lipophilic and produces C9 and C11 dicarboxylic acids, which in vitro inhibit tyrosinase
Flaccid bullae are easily ruptured, resulting in multiple erosions and crusted plaques. B. Involvement of the oral mucosa, which is almost invariable, may present with erosions on the gingiva, buccal mucosa, palate, posterior pharynx, or tongue
may elicit the separation of the epidermis (Nikolsky’s sign).
Pemphigus vulgaris
Histology: acantholytic blister formed in suprabasal layer of epidermis
Cell surface deposits of IgG on keratinocytes
autoantigens
Dsg3 (plus Dsg1 in patients with skin involvement)
olymorphic autoimmune subepidermal blistering disease usually seen in the elderly. Initial lesions may consist of urticarial plaques; most patients eventually display tense blisters on either normal-appearing or erythematous skin
BULLOUS PEMPHIGOID
The major histocompatibility complex class II allele HLA-DQβ1*0301 is prevalent in patients with BP. Though most cases occur sporadi- cally, BP can be triggered by medications (e.g., furosemide, dipeptidyl peptidase-4 inhibitors, immune checkpoint inhibitors), ultraviolet light, or ionizing radiation. Several studies have shown that BP is associated with neurologic diseases (e.g., stroke, dementia, Parkinson’s disease, and multiple sclerosis).
Acute cutaneous lupus erythematosus (LE). A. Acute cutaneous LE on the face, showing prominent, scaly, malar erythema. Involvement of other sun-exposed sites is also common. B. Acute cutaneous LE on the upper chest, demonstrating brightly erythematous and slightly edematous papules and plaques.
Gottron’s papules. Dermatomyositis often involves the hands as erythematous flat-topped papules over the knuckles. Periungual telangiectasias are also evident.
Dermatomyositis. Periorbital violaceous erythema characterizes the classic heliotrope rash.
cleroderma showing acral sclerosis and focal digital ulcers.
Scleroderma often eventuates in development of an expressionless, masklike facies.
Adverse drug rxn type Vasculitis, serum sickness, drug- induced lupus
Type III
Immune Complex IgG + Antigen
Adverse drug reaction type ?
SJS/TEN Morbilliform eruption
Type IVc
T lymphocyte– mediated cytotoxic T lymphocyte inflammation
rare reaction (0.01–0.1%) usu- ally occurs between the third and tenth days of therapy with ___ usually in women. Common sites are breasts, thighs, and buttocks
Lesions are sharply demarcated, erythematous, or purpuric, and may progress to form large, hemorrhagic bullae with necro- sis and eschar formation.
Warfarin necrosis
Uritcaria
Angioedema
Anaphylaxis?
Type I IGe Mediated
Drug-induced hemolysis, thrombocytopenia (e.g., penicillin)
Type II IgG mediated cytoxicity
Tuberculin skin test, contact dermatitis
Type IVa
T lymphocyte– mediated macrophage inflammation
DIHS
Morbilliform eruption
Type 4b
T lymphocyte– mediated eosinophil inflammation
L-4, IL-5, IL-13 TH2 cells Eosinophils
Toxic erythema of chemotherapy.
Allergic contact dermatitis (bullous) due to adhesive tape.
Morbilliform drug eruption.
presents with a prodrome of fever and flu-like symptoms for several days, followed bythe appearance of a diffuse morbilliform eruption, usually involving the face
Drug-induced hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms (DIHS/DRESS
DIHS is a systemic drug reaction also known as DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome; because eosinophilia is not always present, the term DIHS is preferred. Clinically, DIHS presents with a prodrome of fever and flu-like symptoms for several days, followed bythe appearance of a diffuse morbilliform eruption, usually involving the face
60-5 Fixed drug eruption
characterized by blisters and mucosal/epider- mal detachment resulting from full-thickness epidermal necrosis in the absence of substantial dermal inflammation
with >30% detachment
TEN
10–30% epidermal detachment
SJS TEN overkap
medications that cause DIHS /DRESS
** allopurinol** classically induces DIHS with renal involvement; cardiac and lung involvement are more common with minocycline; gastrointestinal involvement is almost exclusively seen with abacavir; and some medications typically do not induce eosinophilia (abacavir, dapsone, lamotrigine). The cutaneous reaction usually begins 2–8 weeks after the drug is started and persists after drug cessation. Signs and symptoms may continue for several weeks, especially those associated with hepatitis. The eruption recurs with rechallenge, and cross-reactions among aromatic anticonvulsants, including phenytoin, carbamazepine, and phenobarbital, are com- mon. Other drugs causing DIHS include antibacterial sulfonamides and other antibiotics. Hypersensitivity to reactive drug metabolites, hydroxylamine for sulfamethoxazole and arene oxide for aromatic anticonvulsants, may be involved in the pathogenesis of DIHS. R
describes cases in which the total body surface area of blistering and eventual detachment is <10%
SJS
Patients with SJS/TEN initially present with fever >39°C (102.2°F); sore throat; conjunctivitis; and acute onset of painful dusky, atypical, target-like lesions (Intestinal and upper respiratory tract involvement are associated with a poor prognosis, as are older age and greater extent of epidermal detachment. A
Drugs that most commonly cause SJS/TEN
Drugs that most commonly cause SJS/TEN are sulfonamides, allopurinol, antiepilep- tics (e.g., lamotrigine, phenytoin, carbamazepine), oxicam NSAIDs, β-lactam and other antibiotics, and nevirapine. Frozen-section skin biopsy may aid in rapid diagnosis.
Target like lesion in SJS
Patients with SJS/TEN initially present with fever >39°C (102.2°F); sore throat; conjunctivitis; and acute onset of painful dusky, atypical, target-like lesions
Tx for SJS TEN
immediate discontinuation of the suspected drug, and meticulous supportive ther- apy in an intensive care or burn unit. Fluid management, atraumatic wound care, infection prevention and treatment, and ophthalmologic and respiratory support are critical. Early administration of systemic glucocorticoids, intravenous immunoglobulin, cyclosporine, or etaner- cept may improve disease outcomes, but randomized studies to evalu- ate potential therapies are lacking and difficult to perform
four (4) main questions to answer regarding a suspected drug eruption:
There are four main questions to answer regarding a suspected drug eruption:
1. Is the observed rash caused by a medication?
2. Is the reaction severe or evolving with systemic involvement?
3. Which drug or drugs are suspected, and should they be withdrawn? 4. What recommendation can be made for future medication use?
drugs that causes Drug-induced hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms (DIHS/DRESS))
Anticonvulsants, sulfonamides, allopurinol, minocycline
Cutaneous small-vessel vasculitis (CSVV, leukocytoclastic vasculitis
Dx? diffuse, deep red morbilliform eruption with facial involvement; facial and acral swelling
Fever, lymphadenopathy, hepatitis, nephritis, myocarditis, eosinophilia, atypical lymphocytosis
drinking allopurinol
Drug-induced hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms (DIHS/DRESS)
Fritzpatrick classification of skin type and sunburn sensitivity
Monitoring for methotrexate tx
LFTs, CBC, renal function (every 4-8 weeks)
Algorithm for the diagnosis of a patient with photosensitivity
Cyclosporine
BP, renal function (every 2-3 months)
Biologics monitoring labs?
TB testing before initiation
CASPAR Criteria
pathophysiology of psoriasis
- Autoimmune Mechanism
- Dysregulated T-cell mediated immune response (Th1, Th17 pathways).
- IL-23/IL-17 axis plays a major role.
- Overproduction of TNF-α, IL-17, IL-22, and IL-23 drives inflammation.
- Keratinocyte Hyperproliferation
- Abnormal differentiation and proliferation of keratinocytes, leading to thickened epidermis (acanthosis), parakeratosis (retention of nuclei in stratum corneum), and elongated rete ridges.
- Angiogenesis & Inflammation
- Increased vascularization in the dermis due to VEGF activation.
Epidemiology of psoriasis
- Prevalence: Affects 2-3% of the global population.
- Age of Onset: Bimodal peaks at 15-30 years (early onset) and 50-60 years (late onset).
- Gender: Equal prevalence in males and females.
- Genetics: Strong genetic component; associated with HLA-Cw6.
