📚 Question Bank

Hypothermia is seen as a complication of erythroderma due to increased skin perfusion. There is no hyperthermia.

The main complications of erythroderma are hemodynamic and metabolic disturbances.

Option A: Increased skin perfusion results in highoutput cardiac failure. Fluid loss by transpiration may lead to hypovolemia.

Option B: Hypoalbuminaemia is due to increased protein loss from exfoliated scales.

Option C: Cutaneous, subcutaneous, and respiratory infections are common and pneumonia remains the commonest cause of death.

The given image is that of pompholyx, a distinct type of hand eczema. It shows confluent vesicles that are painful and pruritic.

It is also called vesicular eczema of palms and soles. This gives a sago grain or tapioca vesicle appearance.

Predisposing factors:

• Atopy
• Naturally dry skin
• Allergic or irritant dermatitis - chromate, epoxy glues, and rubber
• Filaggrin gene mutations are predisposing factors
• Treatment:
• First-line - Hand care advice, irritant, and allergen avoidance
• Second-line - topical corticosteroids
• Third line:
• Alitretinoin
• PUVA
• Azathioprine
• Ciclosporin
• Methotrexate

The image below shows pompholyx.

Nickel is the most frequent contact allergen for contact dermatitis. Most of its salts (nickel chloride, nickel sulfate) are readily soluble in water and sweat and have strong sensitizing properties.

It is more common in women than in men. Jewelry and metal components of clothing are the usual sources of nickel in prolonged contact with the skin.

Allergic contact dermatitis is an inflammatory reaction to a substance (allergen) that causes an eruption only in those individuals previously sensitized by the same molecule. It is a

delayed-type of hypersensitivity (type IV). Substances causing allergic contact dermatitis:

• Chromium
• Palladium
• Gold
• Vegetable matter
• PPD in hair dye

The diagnosis is made by a patch test.

The above scenario is suggestive of irritant contact dermatitis which is the cutaneous response to the physical/toxic effects of a wide range of environmental exposures. It is not an immunologically

mediated reaction.

Irritant contact dermatitis is also called wear and tear dermatitis. Examples include housewives eczema due to soaps and detergents and wetwork, napkin or diaper rash.

Treatment includes avoidance of irritants, personal protection, and 'barrier creams'.

Irritant contact dermatitis

Not an immunologically med iated reaction

It can occur in anyone witho ut predisposing factors

Sensitization is not required

Allergic contact dermatitis

Immunologically mediated re action (type-IV delayed hyper sensitivity)

It only occurs in those indivi duals with a history of atopy

Sensitization phase required

The given history points towards the diagnosis of photoallergic contact dermatitis. Photopatch test is used to diagnose this condition.

It is a delayed-type IV hypersensitivity reaction with a predilection for photo exposed sites with welldemarcated margins where the skin is covered by clothing (at the collar and ‘V’ of the neck, on the backs of the hands, and on the ankles). It spares the skin behind the earlobe (Wilkinson’s triangle) since it is a photo-protected site.

Photopatch test: The standard patch test units are applied in two sets (on either side of the spine) and kept covered. One set of patches is removed and exposed to UVA. After irradiation, the other set of patches are also removed and both the sites are covered again for 48 hours. A positive reaction on the irradiated side only is an indication of photoallergy

The image below shows a photopatch test showing reaction after exposure to UVA only.

The gold standard test for airborne contact dermatitis is a patch test.

Patch testing is done to document sensitivity to a specific antigen. Patch test antigens comprising suspected allergens are applied to the patient’s back and covered for 48 hours. After the patch is removed, the area is examined for delayed type of hypersensitivity.

The image below shows a patch test.

Pityriasis rosea is not a cause of erythroderma.

The most common causes of erythroderma in decreasing order of frequency are:

• Eczema of various subtypes including seborrheic dermatitis
• Psoriasis
• Lymphoma and leukemia
• Drugs - phenylbutazone, phenytoin, carbamazepine, gold salts, lithium, cimetidine
• Hereditary disorders - ichthyosiform erythroderma, pityriasis rubra pilaris
• Pemphigus foliaceus
• Other skin diseases - lichen planus, dermatophytosis, crusted scabies, dermatomyositis

The image shows atopic dermatosis.

Atopic dermatosis is a relapsing inflammatory skin disorder that is common in infancy and presents differently in different age groups. It is characterized by pruritus leading to lichenification.

Clinical features:

• Infants - The lesions most frequently start on the face, and then, the extensor aspect of the
• knees and elbows are involved.
• Children: Dry, scaly, pruritic, excoriated papules and plaques in the flexural areas and neck.
• Adults: Lichenification and dry, fissured skin in a flexural distribution.

The image shows multiple wheals in acute spontaneous urticaria. It is mediated by immunological and non-immunological mechanisms.

The primary mechanism of urticaria is mast cell degranulation triggered by immune

(IgE-mediated) or non-immune (cytokines, complement) mechanisms, which cause the release of histamine. This increases vascular permeability and vasodilation.

It can be acute (lt;6 weeks) or chronic (gt;6 weeks). Acute spontaneous urticaria can be triggered:

• Hypersensitivity
• Viral infections
• Food allergy
• Drug allergy
• Blood transfusions.

However, the actual cause is unknown in nearly 60 of cases.

It is characterized by wheals, which are evanescent, welldefined, pink, or pale swellings due to reversible dermal edema. It usually fades within hours without pigmentation. Wheals are usually very itchy and associated with a surrounding red flare when they arise.

They may occur anywhere on the body, including the scalp, palms, and soles, in variable numbers and sizes.

This clinical scenario with the development of itchy monomorphic, micropapular wheals that appear within minutes of sweating is suggestive of cholinergic urticaria.

Cholinergic urticaria is an inducible urticaria that is common in adolescents. It occurs to due stimulation of the cholinergic post-ganglionic sympathetic nerve supply to eccrine sweat glands. It

may be triggered by a rise in core body temperature, spicy food, or emotion and lasts for a few minutes to 1-2 hours.

Symptomatic dermographism refers to an exaggerated wheal-flare response to physical stimulus, associated with severe itching. It is not a feature of this condition.

This clinical scenario is suggestive of solar urticaria. The wheals develop within minutes of sun exposure and are common on sun-exposed areas.

Solar urticaria is a type of induced urticaria that occurs in response to visible or UV radiation and usually fades within 1-2 hours.

Option A: Cholinergic urticaria presents with small wheals that occur due to sweating and a rise in core body temperature. Though it can also occur following sun exposure, it is more pronounced in the covered parts of the body, where the temperature is higher.

Option B: Heat contact urticaria is a rare form of urticaria that develops following localized warming of skin. It lasts for about one hour.

Option C: Polymorphic light eruption, urticarial lesions appear hours later and last for days after exposure to sunlight.

This clinical scenario is suggestive of dermographism, which is commonly elicited in chronic urticaria patients.

It is an urticarial reaction in response to pressure or trauma to the skin. It is the most common type of inducible urticaria.

Simple dermographism or factitious urticaria refers to the triple response of local erythema due to:

• Capillary vasodilatation
• Edema
• Surrounding flare

The eliciting stimulus determines the shape of the wheals, but they are often linear from scratching or stroking.

In lt;5 of cases, symptomatic dermographism can occur. It is characterized by severe, disproportionate itching that is worse at night.

Other rare forms of dermographism associated with urticaria are cholinergic dermographism, red dermographism, and delayed dermographism.

The given image showing white lines that developed in response to light pressure on the skin is suggestive of white dermographism. It is pronounced in atopic dermatitis.

It is due to an abnormal vascular response, where capillary vasoconstriction occurs in response to light stroking of the skin. While it can occur normally, it is more pronounced in patients with eczema. Tight clothing is a common triggering stimulus. It causes white lines in areas where pressure has been applied, as shown below.

Note: Black dermographism is characterized by skin discoloration after pressure from a metallic object.

This clinical scenario and image showing wheals are suggestive of acute urticaria. The best initial treatment is oral antihistamines.

The lesions are due to histamine release caused by mast cell degranulation as a result of immune and non-immune mechanisms. The treatment is as follows:

• First-line: Second generation non-sedating antihistamines.
• Second-line: Oral corticosteroids and leukotriene receptor antagonists
• Third-line: Immunomodulators like cyclosporine and tacrolimus
• Fourth-line: Omalizumab, an antibody targeted against IgE

The given image shows urticaria pigmentosa lesions on the trunk of a child. It is the commonest type of cutaneous mastocytosis. It occurs due to an increased number of mast cells in the skin.

The mast cells accumulate in tissues due to a gain-offunction mutation of KIT. The symptoms occur due to the release of mast cell-derived mediators. The age of onset is in the first year in the childhood type and 20–40 years in the adult type.

It presents with numerous reddishbrown or pale monomorphic maculopapules, plaques, or nodules in a symmetrical distribution. Lesions can occur anywhere but are common over trunk and thighs. The palms and soles are usually spared. It can also present with bullous lesions that heal without scarring.

Treatment includes:

• Avoiding physical stimuli that trigger mast cell degranulation- temperature extremes, pressure, alcohol
• Antihistamines
• Mast cell stabilizers
• Topical and oral corticosteroids
• PUVA therapy
• Tyrosine kinase inhibitors like imatinib.

Darier's sign is seen in urticaria pigmentosa. It refers to the development of urticaria and erythema around the lesions after mild trauma, including scratching or rubbing of the lesion.

Urticaria pigmentosa is the most common pattern of cutaneous mastocytosis, which occurs due to an increased number of mast cells in the skin. It presents with reddish-brown or pale maculopapules, plaques, nodules in symmetric distribution, sparing the palms and soles.

Darier's sign is not specific for mastocytosis as it is also rarely seen in juvenile xanthogranuloma and acute lymphoblastic leukemia.

Note: Pseudo-Darier sign is seen in soft tissue hamartoma, with piloerection and transient induration after stroking the lesions. Darier's disease is an autosomal dominant disorder, characterized by hyperkeratotic papules and plaques along with nail changes.

Angioneurotic edema or Quincke's disease is characterized by non-pitting edema of the face, lips, and mucous membranes.

Angioedema is the accumulation of fluid in the subcutaneous and submucosal layers. It is common in the lips, eyelids and genitalia due to laxity of tissue in these areas. It can present with or without wheals.

Quincke's disease refers to the hereditary form of angioedema without wheals. There is no itching. It is bradykinin-mediated and is usually linked to abnormality or deficiency of C1esterase inhibitor (C1INH) enzyme. Other non-hereditary causes include acquired C1INH deficiency and use of ACE inhibitors.

Angioedema with wheals is a type of spontaneous or inducible urticaria.

The image shows subcutaneous and submucosal edema of the face and lips without wheals. Along with the history, a diagnosis of hereditary angioedema (HAE) is most likely. Type I HAE is the most common form (85).

There are three types of hereditary angioedema (HAE):

• Type 1 (85): C1INH deficiency
• Type 2 (15): Dysfunction of C1-INH, but normal levels
• Type 3 (rare) : Normal C1-INH levels and function

HAE occurs due to a mutation in the SERPING1 gene, which codes for the C1 esterase inhibitor

(C1INH). It is also called angioneurotic edema or Quincke's disease. C1INH enzyme normally inhibits the following:

• Complement system
• Kallikrein system
• Factor XII or Hageman factor

In HAE, loss of C1INH activity leads to loss of inhibition of these above processes. This leads to decreased C4 and C2 levels and bradykinin accumulation.

The image shows subcutaneous and submucosal edema of the face without wheals, pointing towards a diagnosis of angioedema. Hereditary angioedema type 1 is characterized by decreased C1INH levels and decreased C2 and C4 with normal C1q levels.

Angioedema without wheals can be due to hereditary or acquired causes. Levels of antigen C1q help in differentiating between them. In hereditary angioedema, the C1q level is normal whereas, in acquired angioedema, the C1q level is usually low.

The given clinical scenario is suggestive of ACE inhibitor-induced angioedema, which is due to inhibition of ACE resulting in reduced bradykinin metabolism. Increased bradykinin level produces vasodilation causing angioedema. It typically occurs within 3 weeks of starting treatment but can occur anytime.

ACE inhibitorinduced angioedema is common in older people on treatment with ACE inhibitors.

It is a class effect seen with all ACE inhibitors. It is uncommon with angiotensin receptor blockers.

It predominantly affects the face and oropharynx. Symptoms may be severe, and laryngeal involvement may be life-threatening.

The given clinical scenario is suggestive of anaphylaxis. It is a medical emergency. It is a severe form of type I hypersensitivity. Cinical features include:

• Urticaria
• Angioedema
• Severe pruritus
• Bronchospasm
• Laryngeal edema
• Hypotension.
• Sense of impending doom

The first step in management is to secure the airway. This must be followed by intramuscular administration of epinephrine in the lateral thigh. The dose is 0.3 to 0.5 ml of 1:1000 solution. It can be repeated after 10-15 minutes if necessary.

Option A: Angioneurotic edema is not associated with pruritus or systemic features. Option C: Generalized acute urticaria is not associated with systemic features.

Option D: Steakhouse syndrome refers to oesophageal impaction of food. It presents with dysphagia. There is no respiratory distress.

Cutis marmorata refers to the pinkish-blue mottled or marbled appearance when subjected to cold temperatures.

It is seen throughout infancy and in 50 of children. It is caused by simultaneous dilation and contraction of the superficial capillaries. Rewarming restores the skin to normal. This is a physiological finding and requires no treatment. However, persistent cutis marmorata may be seen in trisomies 18 and 21.

Note: Cutis marmorata telangiectatica congenita is a distinct vascular developmental disorder and is easily distinguished as it is fixed (it does not disappear on rewarming), and it may be associated with a variety of other anomalies such as limb growth or renal anomalies.

The given image shows characteristic target lesions of erythema multiforme. This most commonly occurs following a herpes simplex virus infection.

The common triggers are:

• Herpes simplex infection
• Mycoplasma infection
• Bacterial infections
• Fungal infections
• Vaccinations
• Malignancy- carcinoma, lymphoma, leukemia
• Drugs- sulfonamides, rifampicin, penicillins, hydantoin derivatives
• Miscellaneous- lupus erythematosus (Rowell Syndrome), sarcoidosis, polyarteritis nodosa

Erythema multiforme is best regarded as a selflimiting cytotoxic dermatitis resulting from cellmediated hypersensitivity.

It presents clinically with a spectrum of macular, papular, or urticarial lesions, as well as the classic acral iris or ‘target lesions’.

Target lesions are less than 3 cm in diameter, rounded, and have three zones:

• Central area of dusky erythema or purpura
• Middle paler zone of edema
• Outer ring of erythema with a welldefined edge

Lesions may involve the palms and the trunk. Oral and genital mucosal membranes lesions are associated with erosions

The image below shows target lesions.

Erythema multiforme minor (papular or simplex form) accounts for approximately 80 of cases and is the most common form.

Clinically erythema multiforme presents as macular, papular, or urticarial lesions, as well as the classic iris or ‘target lesions’, distributed preferentially on the distal extremities. Raised atypical target lesions having only two of the zones may also be seen and mucous membranes are rarely involved. Koebnerization accounts for some bizarre clinical distributions.

Photoaggravation of erythema multiforme is well recognized.

The lesions appear in successive crops for a few days and fade in 1–2 weeks, sometimes leaving dusky discoloration.

The image given below shows mucosal involvement in erythema multiforme major

Eczema shows spongiotic dermatitis and not interface dermatitis.

Interface dermatitis includes diseases in which the primary pathology involves the dermo-epidermal junction.

The salient histological findings include:

• Basal cell vacuolization
• Apoptotic keratinocytes (colloid or Civatte bodies)
• Obscuring of the dermo-epidermal junction by inflammatory cells
• Common conditions showing interface dermatitis are:
• Erythema multiforme
• Lichen planus
• Graft versus host disease
• Fixed drug eruptions
• Lupus erythematosus
• Dermatomyositis