Types of Psoriasis

Type	Appearance	Where	% of Cases
Plaque (vulgaris)	Thick silvery-white scale on red plaques	Elbows, knees, scalp, lower back	~80–90%
Guttate	Teardrop-shaped, smaller lesions	Trunk, limbs	~10%
Inverse	Smooth red plaques, no scale	Flexures (armpits, groin, under breasts)	~3–5%
Pustular	White pustules on red skin	Palms, soles (palmoplantar) or generalised	Rare
Erythrodermic	Whole body redness and scaling	Generalised	Rare: emergency

Treatment Ladder

Emollients + topical corticosteroids (mild-moderate)
Topical vitamin D analogues (calcipotriol/betamethasone combination)
Topical coal tar or dithranol (effective but messy)
Phototherapy (UVB narrowband, 2–3 sessions/week for 6–8 weeks)
Systemic: methotrexate, ciclosporin, or acitretin (PUVA/UVB failures)
Biologics (TNF-α blockers, IL-17 inhibitors, IL-23 inhibitors): for moderate-severe disease; PASI score >10

PASI ScoreThe Psoriasis Area and Severity Index (PASI) guides treatment. PASI >10 indicates moderate-severe disease warranting systemic or biologic treatment. Biologics achieve PASI 90 (90% clearance) in most patients.

What triggers psoriasis?

Stress (most common), streptococcal throat infection (especially guttate), skin trauma (Koebner phenomenon), alcohol, smoking, certain medications (beta-blockers, lithium, antimalarials, NSAIDs), and stopping corticosteroids abruptly.

Does psoriasis affect life expectancy?

Moderate-severe psoriasis is associated with increased cardiovascular risk, equivalent to diabetes: due to systemic inflammation. Effective treatment of psoriasis (especially biologics) may reduce cardiovascular risk.

What is psoriatic arthritis?

An inflammatory arthritis developing in ~30% of people with psoriasis. Features: swollen fingers/toes (dactylitis), enthesitis (tendon insertion inflammation), nail changes, and joint damage. Treated with DMARDs and biologics.

Are biologics safe for psoriasis?

Yes. When appropriately screened. Patients need TB screening, hepatitis B/C testing, and baseline infection check before starting. Biologics increase infection risk slightly but are generally very safe and highly effective.

Psoriasis is more than a skin condition

Psoriasis is a systemic inflammatory disease that happens to be visible on the skin, and treating it as purely dermatological misses much of what matters. Up to a third of people with psoriasis develop psoriatic arthritis, which can begin years after the skin disease and, unlike the rash, causes irreversible joint damage if untreated. Any new joint pain, morning stiffness, swollen fingers or toes, or heel pain in someone with psoriasis should prompt assessment rather than being attributed to unrelated wear and tear.

Psoriasis also carries an increased burden of cardiovascular disease, metabolic syndrome, fatty liver, inflammatory bowel disease and depression. Severe disease is associated with the greatest excess risk. This is why blood pressure, lipids, glucose and weight are checked periodically rather than only when symptoms arise.

Common triggers and aggravating factors

Streptococcal throat infection, a classic trigger for guttate psoriasis, particularly in younger people.
Skin trauma, including scratches, sunburn and tattoos, which can seed new plaques along the injury.
Medication: lithium, beta blockers, antimalarials, and abrupt withdrawal of oral corticosteroids, which can precipitate severe flares.
Smoking and alcohol, both of which worsen disease and reduce treatment response.
Stress and infection, and in some people, cold dry weather.

Monitoring required by treatment

Topical treatments need little monitoring, but systemic therapies do. Methotrexate requires regular full blood count, liver function and kidney function, since marrow suppression and hepatotoxicity are the main risks. Ciclosporin requires blood pressure and kidney function monitoring and is used for limited periods. Acitretin is teratogenic for years after stopping and requires strict contraception alongside lipid and liver monitoring. Biologic therapies require screening for tuberculosis and hepatitis before starting. Knowing which tests belong to your treatment, and roughly when they are due, is a practical way to avoid gaps.

References

The clinical information on this page is drawn from peer-reviewed sources indexed by the US National Library of Medicine. Links go to the source so you can read it yourself.

Psoriatic Arthritis. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK547710
Oliveira Mde F, Rocha Bde O, Duarte GV. Psoriasis: classical and emerging comorbidities. An Bras Dermatol. 2015;90(1):9-20. doi:10.1590/abd1806-4841.20153038 · PMID 25672294

Psoriasis: Types, Triggers & Modern Treatment Options