Dermatological presentations of systemic disease

Question 1

Erythema nodosum

Answer 1

A: Inflammation of fat cells beneath the skin
Can be from autoimmune (IBD, Bachet’s), Drugs (OCP, sulphonamides), idiopathic, infection (strep, TB, hep C), malignancy, pregnancy, sarcoidosis

S: Red, tender nodules or lumps, usually on the shins

D: Underlying cause

T: Self-limiting, so focus on alternative cause. If it doesn’t improve potassium iodide can be given.

Question 2

Pyoderma gangenosum

Answer 2

A: Neutrophilic disorder causing skin ulceration.
Thought to be autoimmune and associated with IBD, rheumatoid arthritis and haematological disorders (myeloma).

S: Begins as a small pustule then rapidly ulcerates. Ulcers rapidly grow in size and are usually painful with a purple border. Usually lower limbs.

D: Underlying cause

T: Topical or systemic steroids

Question 3

Dermatitis Herpetiformis

Answer 3

A: Skin manifestation of coeliac disease.

S: Intensely itchy rash, commonly on extensor surfaces.

D: Skin biopsy shows IgA

T: Gluten free diet, dapsone for itching/blistering, steroids may be needed.

Question 4

Erythema multiforme

Answer 4

A: Hypersensitivity reaction usually triggered by an infection. Herpes simplex and mycoplasma pneumonia are the commonest cause.
Other causes include drugs (antibiotics, sulphonamides), infection (EBV, hep B, histoplasmosis), lupus, malignancy, pregnancy, sarcoidosis.

S: Target lesions - well demarcated, round, pink, flat lesions, which become raised to form a plaque with a pale ring around the centre.

D: Clinical

T: Self-limiting

Question 5

Acanthosis nigricans

Answer 5

A: Common causes include insulin resistance, obesity, PCOS and paraneoplastic (from GI malignancy).

S: Brown hyperpigmentation of the skin, commonly at groin or axilla.

D: Underlying cause

T: Underlying cause

Question 6

Thrombophlebitis migrans

Answer 6

A: Paraneoplastic syndrome often from pancreatic or lung malignancy.

S: Recurrent thrombophlebitis.
Tender, palpable blood vessels with overlying redness and swelling.

D: Can be confirmed by Doppler studies, but investigation of malignancy is needed.

T: Rest, elevation, compression stockings, NSAIDs.

Question 7

Lupus vulgaris

Answer 7

A: Persistent and progressive cutaneous manifestation of mycobacterium tuberculosis.

S: Small, sharply defined reddish-brown lesions with a gelatinous consistency.

D: Confirm with skin biopsy

T: TB treatment

Question 8

Lupus pernio

Answer 8

A: Cutaneous manifestation of sarcoidosis

S: Large, bluish-red/purple nodules on face, hands or feet.

D: Skin biopsy shows granulomatous infiltration.

T: Sarcoidosis treatment.

Question 9

Necrobiosis lipoidica

Answer 9

A: Rare skin disorder that affects the shins of insulin-dependent diabetics.

S: Yellow/brown, waxy patches on the shins. Typically painless and slowly growing.

D: -

T: Topical steroids, intralesional steroid injections, aspirin and dipyridamole, ciclosporin or PUVA treatment.

Question 10

Granuloma annulare

Answer 10

A: Chronic skin disease caused by granulomatous inflammation occurring withing the dermis. Usually idiopathic but can be associated with autoimmune diseases (DM, thyroid, SLE) or malignancy.

S: Usually a ring of small, red papules over backs of forearms, hands or feet with a tendency to joints or knuckles. May be tender if knocked.

D: Skin biopsy can confirm if needed

T: Often resolve spontaneously. But can give topical, intralesional or systemic steroids, topical iniquimod or tacrolimus.