DERM Revision 3 Flashcards

Question

A patient takes penicillin for an infection. They come out in targetoid lesions. What type of hypersensitivty reaction is this? Type 1 Type 2 Type 3 Type 4

Answer 1

Type 1 Type 2 Type 3 **Type 4** EM is considered a cell-mediated (type IV) hypersensitivity reaction, which is an abnormal cell-mediated reaction initiated by T cells. The exact mechanism leading to EM is incompletely understood, but it appears to be an abnormal immune reaction to a drug metabolite or viral antigen that becomes expressed by keratinocytes within the skin

Answer 2

Management * EM typically develops over 3-5 days and improves over 2 weeks. Some patients may get persistent or recurrent episodes. * Stop the drug * Treat the underlying infection * Treat with a week of **oral** **prednisolone** if severe mucosal pain/ difficulty eating

Answer 3

**Stevens-Johnson syndrome** is a severe systemic reaction affecting the **skin and mucosa** that is almost always caused by a **drug reaction**. **Presentation**: * **Patients** usually start with non-specific symptoms of **fever, cough, sore throat, sore mouth, sore eyes and itchy skin**. * They then develop a **purple or red rash** that **spreads across the skin and starts to blister**. * **Nikolsky sign is positive** in erythematous areas - blisters and erosions appear when the skin is rubbed gently ## Footnote **NB**: Nikolsky sign = where very gentle rubbing of the skin causes it to peel away

Answer 4

**SPANLOC** * **S**ulphonamide * **P**enicillin * **P**henytoin * **Al**lopurinol * **N**SAIDS * **L**amotrigine * **O**CP * **C**arbamazepine Most commonly caused by drugs. Less commonly infection eg **Mycoplasma**

Answer 5

**Dx**: - **skin biopsy** Severity: - **SCORTEN** ## Footnote sum of five points or more indicates a mortality risk of over 90%

Answer 6

**staphylococcus** **aureus** bacteria that produces **epidermolytic** toxins. These toxins are **protease enzymes** that break down the **proteins that hold skin cells together** When a skin infection occurs and these toxins are produced, the skin is damaged and breaks down. This condition usually affects children under 5 years. Older children and adults have usually developed immunity to the epidermolytic toxins.

Answer 7

**Fever**: - High fever (>38.9°C) **Rash**: - A **diffuse**, **blanching** **erythroderma** resembling **sunburn** usually appears early in the disease course. - **Desquamation**, particularly on the **palms and soles**, typically occurs **one to two weeks after the onset of illness** **Myalgias and arthralgias** are frequently reported; **Hypotension**: - Hypotension or shock may be present, often manifesting as systolic blood pressure less than 90 mmHg.

Answer 8

* Admit * Fluids * **IV flucloxacillin** and **clindamycin** *Clindamycin suppresses toxin production, while flucloxacillin targets the bacterial cell wall.* * If methicillin-resistant Staphylococcus aureus (MRSA) is suspected, **vancomycin** or **daptomycin** can replace flucloxacillin.

Answer 9

**Type 1** – Polymicrobial (anaerobes + aerobes) **Type 2** – Group A beta-haemolytic streptococci **Type 3** – Clostridium perfringens; also associated with Vibrio species infection from seafood ingestion or water contamination of wounds. **Type 4** - Fungal infection

Answer 10

**Co-amoxiclav**

Answer 11

Clinical knowledge summaries recommend a **topical imidazole, undecenoate, or terbinafine first-line**

Answer 12

**Erythema ab igne** If the cause is not treated then patients may go on to **develop squamous cell skin cancer**.

Answer 13

Features * **target lesions** * initially seen on the **back of the hands** / **feet before spreading to the torso** * **upper limbs** are more commonly affected than the lower limbs * **pruritus** is occasionally seen and is usually **mild**

Answer 14

Erythrasma is a superficial bacterial skin infection caused by **Corynebacterium minutissimum** Examination with Wood's light reveals a **coral-red fluorescence.** **Topical miconazole** or antibacterial are usually effective. Oral erythromycin may be used for more extensive infection

Answer 15

**Erythrasma** is a generally asymptomatic, flat, slightly scaly, pink or brown rash usually found in the groin or axillae. It is caused by an **overgrowth** of the **diphtheroid Corynebacterium minutissimum** Looks the same as acanthosis nigricans WITHOUT thickening/velvet like texture of the skin

Answer 16

Causative organisms **dermatophytes** account for around 90% of cases mainly **Trichophyton rubrum** **yeasts** account for around 5-10% of cases e.g. **Candida**

Answer 17

**Investigation**: - **nail clippings +/- scrapings** of the affected nail for **microscopy and culture** - should be done for all patients if antifungal treatment is being considered **Mangement**: - **None** if asymptomatic and unbothered - **if limited involvement** (≤50% nail affected, ≤ 2 nails affected, more superficial white onychomycosis): **topical treatment with amorolfine 5% nail lacquer**; **6 months** for **fingernails** and **9 - 12 months** for **toenails** - **extensive**: **oral terbinafine** is currently recommended first-line; **6 weeks - 3 months therapy** is needed for **fingernail** **infections** whilst **toenails should be treated for 3 - 6 months**

Answer 18

**Limited involvement:** - Topical treatment with **amorolfine** **5% nail lacquer** - Fingernails: 6 months - Toe nails: 9-12 months **Extensive involvement** - : **oral terbinafin** - Fingernails: 6 weeks-3 months - Toe nails: 3-6 months **Candida**: - **oral itraconazole** is recommended first-line; - **'pulsed' weekly therapy** is recommended

Answer 19

**epistaxis** : - spontaneous, recurrent nosebleeds **telangiectases**: - multiple at characteristic sites (lips, oral cavity, fingers, nose) **visceral lesions:** - for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM **family history**: - a first-degree relative with HHT ## Footnote NB only 3 are needed for a definite diagnosis; 2 is a possible diagnosis

Answer 20

**Hidradenitis suppurativa** * Chronic, painful, inflammatory skin disorder. * It is characterized by the development of inflammatory nodules, pustules, sinus tracts, and scars in intertriginous areas * **The axilla is the most common site** * Coalescence of nodules can result in plaques, sinus tracts and **'rope-like' scarring.**

Answer 21

**Acute flares**: - can be treated with **steroids** (intra-lesional or oral) or **flucloxacillin**. - **Surgical incision** and **drainage** may be needed in some cases. **Long-term disease:** - can be treated with **topical** (**clindamycin**) or **oral** (lymecycline or clindamycin and rifampicin) **antibiotics**.

Answer 22

1. **topical aluminium chloride** preparations are first-line. Main side effect is skin irritation 2. **iontophoresis**: particularly useful for patients with palmar, plantar and axillary hyperhidrosis 3. **botulinum toxin**: currently licensed for axillary symptoms 4. **surgery**: e.g. Endoscopic transthoracic sympathectomy. Patients should be made aware of the risk of compensatory sweating

Answer 23

Tx: - **Hydrogen peroxide 1% cream** for 'people who are not systemically unwell or at a high risk of complications' - topical antibiotic creams: **topical fusidic acid**; **topical mupirocin** should be used if fusidic acid resistance is suspected - Extensive disease: **oral flucloxacillin**; **oral erythromycin** if penicillin-allergic

Answer 24

**Early** **keloids**: - **triamcinolone** **Excision** is sometimes used (but can risk further keloid scarring)

Answer 25

**Leukoplakia** - is a **premalignant** **condition** which presents as **white, hard spots** on the **mucous** **membranes** of the **mouth**. - Differentiae from candiasis and lichen planus if they can be '**rubbed** **off**' - oral hairy leukoplakia (OHL), a specific type of leukoplakia, is caused by the **Epstein-Barr virus (EBV)** - Need a biopsy to exclude **squamous cell carcinoma** as this can transform in about 1% patients

Answer 26

**Lichen planus** - pruritic eruption on the shins Skin disorder of unknown aetiology, most probably being immune-mediated.

Answer 27

Pruritic Purple Polygonal Planar Papules Plaques

Answer 28

**potent topical steroids** are the mainstay of treatment **benzydamine mouthwash** or spray is recommended for oral lichen planus

Answer 29

It is an inflammatory condition that usually affects the **genitalia** and is more **common in elderly females.** Lichen sclerosus leads to **atrophy** of the **epidermis with white plaques** forming. **Features**: * **white** **patches** that may scar * **itch** is prominent * may result in **pain** during **intercourse** or **urination**

Answer 30

**Treatment**: * topical steroids and emollients Follow up due to risk of **vulval cancer**

Answer 31

Mycosis fungoides is a **rare form of T-cell** **lymphoma** that affects the **skin**.

Answer 32

lesions tend to be of **different colours** in contrast to eczema/psoriasis where there is greater homogenicity

Answer 33

**Pellegra - B3 deficiency** The classical features are the **3 D's - dermatitis, diarrhoea and dementia.** Dermatitis (brown scaly rash on sun-exposed sites - termed Casal's necklace if around neck)

Answer 34

A condition typically seen in women aged 20-45 years old. **Topical corticosteroids, and to a lesser extent, inhaled corticosteroids are often implicated** in the development of the condition. **Management**: * steroids may worsen symptoms * should be treated with topical or oral **antibiotics**