Pustular Psoriasis

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Pustular psoriasis

Pustular psoriasis tends not to look like plaque psoriasis, although plaque and pustular psoriasis can coexist or one may follow the other.

The main distinguishing feature of pustular psoriasis is the appearance of pus spots surrounded by red skin. This doesn’t mean that there is any infection present. The spots simply show that the skin has been invaded by the same white blood cells that would be seen if there were to be an infection present.

It can be triggered by some internal medications, irritating topical agents, ultraviolet light overdoses, pregnancy, systemic steroids (especially sudden withdrawal of systemic or topical steroids), infections, perspiration or emotional stress.

Generalised pustular psoriasis

Generalised pustular psoriasis is a rarer form of the condition, and especially rare in children. It can be abrupt, and triggered by an infection, pregnancy, low thyroid activity or any of a number of different drugs. It can cause fever, chills, severe itching, rapid pulse rate, exhaustion, anaemia, weight loss, muscle weakness and/or joint pain. Sometimes these attacks are followed by milder outbreaks of psoriasis. With this type, the pustules occur all over the body – patients can often  become quite unwell and, as such, generalised pustular psoriasis often requires hospital in-stay treatment. Please do note that this is a rare form of psoriasis

Palmer-Plantar Pustulosis (PPP)

Another form of pustular psoriasis, palmer-plantar pustulosis, causes pustules on the palms and soles of the feet. It tends to occur in people between the ages of 20 and 60, and is more common in people who smoke. Infect ion and stress are suspected trigger factors. PPP is normally recognisable by large yellow pustules up to 5cm in diameter in fleshy areas of hands and feet, such as the base of the thumb and the sides of the heels. It may be painful. The pustules then turn brown and drop off or peel. PPP is usually cyclical with new crops of pustules followed by periods of low activity. This form of psoriasis affects approximately 5% of people with psoriasis. It tends to go in cycles of:

  1. erythema (reddening of the skin) followed by
  2. formation of pustules; and
  3. scaling of the skin.

Topical therapies are usually a first-line treatment. PUVA and methotrexate are also sometimes used to clear the attack. However this type of psoriasis can be a little more difficult to manage.

In most episodes of pustular psoriasis these will last for a few weeks then disappear or return to erythrodermic psoriasis.

Acrodermatitis Continua of Hallopeau

Another rare type of palmar-plantar pustular psoriasis, acrodermatitis continua of Hallopeau is characterised by skin lesions on the ends of the fingers and sometimes on the toes. The eruption occasionally starts after local trauma. Often the lesions are painful and disabling, with the nails often deformed, and bone changes may occur. This condition is quite hard to treat satisfactorily.

Treatment

Pustular psoriasis and PPP are usually treated with topical treatments. Sometimes topical steroids under thin dressings are prescribed. Pustular psoriasis can be stubborn to treat so sometimes other treatment regimes typically used for plaque psoriasis may be tried. Although not completely proven, for those who smoke, quitting appears to reduce the number of pustules as well as significantly reducing the erythema (redness) and desquamation (shedding of skin).

The main aims of the treatment of generalised pustular psoriasis are to restore the skin’s barrier function, prevent further loss of fluid, stabilise the body’s temperature and restore the skin’s chemical balance. Imbalances, which can occur, might put added strain on the heart and kidneys, especially in older people. Because of possible complications with this form of psoriasis, if you’re affected you should seek medical care immediately. The likelihood of hospitalisation for a short period of time depends on the severity of the outbreak. When hospitalised, bed rest, mild sedation, bland topical therapy, rehydration and avoiding excessive heat loss can improve the situation. It is important to remove as many of the potential trigger factors as possible. In some cases antibiotics are prescribed just in case an infection is also present. In severe cases, where the patient has become exhausted, other medications may be needed.

Methotrexate is the most common treatment for generalised pustular psoriasis. Ciclosporin is also used if your doctor needs to control the symptoms quickly. Oral steroids are often prescribed for those who do not respond to other forms of treatment or who have become very ill, but their use is very controversial. PUVA (the photsensitising drug psoralen plus UVA light) may also be used in the treatment of this condition after it has subsided.

Acrodermatitis continua of Hallopeau tends to be resistant to both topical and systemic treatments for psoriasis, so combinations of therapy may be tried. Most episodes of pustular psoriasis will last for a few weeks then disappear or remit to erythrodermic psoriasis.

Summary

  • Pustular psoriasis is a rare form of psoriasis
  • Severe cases need urgent referral
  • Be aware of the trigger factors
  • PPP is more common in people who smoke
  • It tends to go in cycles
  • Where pustules exist they may not necessarily be infectious
  • Like psoriasis, the pustular version is not contagious.

This article is adapted from the Pustular Psoriasis leaflet. 

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Further information

Always consult a doctor or your healthcare provider