Additional conditions Flashcards
What is Pityriasis rosea ?
- It is an acute viral rash which lasts about 6–12 weeks.
- It is characterised by a herald patch followed by similar, smaller oval red patches that are located mainly on the chest and back.
Who is most commonly affected by pityriasis rosea?
Teenagers & young adults
Many patients with pityriasis rosea have no prodrome, but in a small number of patients what may they give a history of having ?
A history of recent upper respiratory viral infection (cough, cold, sore throat or similar).
What are the clinical features of pityriasis rosea ?
- Solitary lesion ‘Herald patch’ appears 2-4days before onset of rash
- Herald patch = an oval pink or red plaque which is scaly on its inside edge
- Secondary rash occurs = multiple smaller oval scaly (on there inside edge) patches/plaques.
- Christmas tree effect following the ribs
What part of the body does pityriasis rosea mainly affect?
Back & chest.
What is shown in this pic ?
Herald patch - pityriasis rosea
What is shown in this pic ?
They secondary rash in pityriasis rosea
How is pityriasis rosea diagnosed ?
Clinically
What is the treatment of pityriasis rosea?
Self-limiting so no treatment needed.
If itch consider giving 1 or more of the following:
- sedating oral antihistamine (for example chlorphenamine
- An emollient
- A midly-moderately potent TCS
What is lichen planus ?
It is a chronic inflammatory skin condition affecting the skin and mucosal surfaces. There are several clinical types of lichen planus that share similar features on histopathology.
- Cutaneous lichen planus
- Mucosal lichen planus
- Lichen planus of the nails
- Lichenoid drug eruption
What parts of the body does cutaneous lichen planus tend to affect?
Location can be anywhere, but most often front of the wrists, lower back, and ankles.
What are the clinical features of lichen planus ?
- Violaceous (pink/ purple) Papules & polygonal (many angled) plaques that are shiny, flat-topped, firm & have fine white lines crossed across them (Wickhams striae)
- Lesions are itensley itchy
- Plaques can be hypertrophic
- Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
- Oral involvement common (50% of cases) - typically a white-laced pattern on the buccal mucosa
- Nail involvement - thinning of the nail plate & longitudinal ridging seen
What is shown in this pic ?
Oral involvement of lichen planus
What is shown in this pic ?
Nail features seen in lichen planus
Describe what a lichenoid drug eruption is
This refers to a lichen planus-like rash caused by medication
How can lichenoid drug eruptions be distinguished from regular lichen planus ?
- Rash is usually extensive and distirbuted symmetrically over the trunk & limbs
- Wickham striae are usually absent
- Nail and mucous membrane (e.g., mouth) involvement is uncommon
- History of starting a new drug in the past year
What are the characterisitic microscopic features of lichen planus ?
- Hyperkeratosis
- Thickened granular layer
- Jagged (saw-tooth) baseline of epidermis
- A dense band of lymphocytes and histiocytes at the DEJ.
What are the clinical features of vitiligo?
- Well-demarcated patches of white (depigmented) skin
- The peripheries tend to be most affected
- Trauma may precipitate new lesions (Koebner phenomenon)
- Without treatment, individual lesions usually enlarge over time and patches may merge to form extensive geographical patterns.
What is shown in this pic ?
Vitiligo
What clinical feature is shown here ?
Beau’s line - caused by transient arrest in nail growth, which occurs during acute stress/illness
What is shown here ?
Subungual haemorrhage:
- Presents as a discoloured or pigmented nail (reddish, purple, brown, black, or a combination), which may be painless, tender, or painful.
